[ NOTE: NOT so much a direct reply to the OP, who said his girlfriend just finished certification. More intended as a contrarian viewpoint for other readers since the overall thread has been a bit grandmotherish, in my opinion. ]
Not to belittle the FG, but I think it can be dove successfully by new
ish divers - not totally new, but newish. Assuming proper equipment, a well considered dive plan going into it, some prior open saltwater experience, and some prior saltwater experience at similar depths. I would consider AOW the absolute minimum, but AOW + Nitrox a much better choice, diving Nitrox for the trip.
My wife and I have less than 50 dives under the belt and were closer to the 30 mark when we went on the Fling for Labor Day weekend. We had however been deep before (Saba - 130 max, many dives in the 110 - 80 foot range) and have done most of our diving aside from 'training' dives in the Caribbean. We were both AOW and Nitrox certified, diving on our own equipment, with computers.
At the time we talked it over - we had read that it was 'challenging' diving. From what we'd heard at the time, the primary challenges were that the dives are for all practical purposes unguided: you may be booking thru a LDS as an intermediary, but you're mostly diving in your own buddy teams after an up-front briefing by the boat DMs. Which means planning for current and visibility, even if that means being a mooring line flag until you get comfortable. The depth and dive frequency would be what we saw as the second consideration, but as we both had computers and had done up to 3 dives per day before, we thought we would be okay here too. The last consideration then was the potential of rough seas and the confinement of a liveaboard (my wife can get mildly claustrophobic and seasick). Again, we had some open salt water experience (Saba and St. Maarten, the latter actually in semi-rough waters between tropical depressions in the area) so we figured it wasn't our first time for those concerns either. But really comments about a "6 foot giant stride" didn't even register on the radar to either of us as concerns. If you were properly trained to do a giant stride at all, it doesn't get any 'harder' doing it from 6' vs. 3' in my opinion (and I'm a hair under 6' 2" tall, so I'm looking down from that eyeball height). Now 10' might be a different story entirely
So - how did it work out for us? She did all dives but the 2 night dives, for 10 of the 12 possible (3 day trip) and I did all but one of the night dives for 11, buddying with some of the other divers for the second. (We sat out the first night dive together because 5 dives in a day when we'd previously only done 3 max had us a little shellshocked, and I still think it was the right decision for the time.) Neither of us rode the "Dinghy of Shame" because we lost the boat or misjudged currents - although on the first dive we did lose sight of both boat hull and chain for far longer than I'd have thought we did, and were approaching what I considered ascent tank levels (600psi) before we caught sight of the chain and realized we had found our way back correctly after all (no, there weren't any other divers close enough we were able to 'cheat' and follow them). Neither of us sat out a dive because of violating the boat depth rules (one dive sit-out) or air reserves (sit out the rest of the trip). Neither of us had an equipment malfunction or any sort of panic reaction at all - in fact we stepped aside calmly and carefully on egress when another diver or two came up having problems (apparent reverse block once, just a bit low on gas for the other...) We even task loaded a bit with camera on a couple of the dives, requiring an extra stop to hook it to the pull line, and never took advantage of the hung reg either. In fact looking at our dive times I was probably overly conservative - we agreed on a 'half air' turnaround, starting into the current, that got us back into visible range usually with about 1000psi left, and then we'd stay in full sight of boat/mooring until about 600psi and ascend (our consumption is such that even with frequent dives, we're pretty much air rather than nitrogen limited on our dives). There were a number of other divers who got to sit out a single dive on the same trip, although I don't think anyone violated the 'out of air' and sat out the remainder.
So, were my guesses right as to the primary danger/experience points, in hindsight? Somewhat. I'd have to say I did NOT count on the visibility, basing my assumptions on our 60-100+' vis in our prior spots, which here can drop below the 40' type range. The boat disappeared on that first dive a lot sooner than I expected, and I thought I was being pretty cautious doublechecking direction and looking back over my shoulder about every 10 kicks. But our dive 'plan' allowed for that so we were calm in the face of it, after a few "no, YOU tell ME where the &*%$# boat is!!" hand gestures back and forth.
My wife did later admit to me she was a bit apprehensive when she realized when I said we'd be diving alone I'd really meant it, not just 'unguided' - we really were "alone" without even other diver bubble-trails in visibility a good part of the time. But after the initial shock, we got over it. Does that mean we dodged a bullet? Maybe - but then you never know if you're going to handle something like that solo until you actually do it solo the first time, and the ships purposely stop first at the shallower moorings (despite rules that the first dive of the morning is 130' max) to 'assess' their current load of divers unless perhaps they know them all well already or are specifically chartered otherwise.
Current was also something we 'considered' logically, but hadn't had the experience with to really know what we were getting into. I thought I was being hypercautious about going against the current first when starting the dive away from the mooring and turning around at 1/2 air, but even I was surprised by how quickly my compass bearing would change with the water in your face. Again, making the right decisions (I think - chime in anyone if you think we were stupid) in the face of it, on one of the dives with heavier current I called a turn at about 2/3rd air and suggested we just toodle in sight of the mooring line once we got back. It never ceases to amaze me that other divers find it necessary to 'swim away from the pack' while just hanging and occasionally counteracting your drift, I think you see as much if not more and get a better feel for that smaller area.
Even if you have experience with limited vis and currents, there may come a time when either or both exceed your plan and you have to make an educated decision to change the plan. Regardless of how many prior dives you have. That's gotta start somewhere, and by definition you've never had it happen until you've had it happen... I'm not saying throw yourself into the deep blue open your first time, but if you wait to have 'experience' with adverse conditions before you risk adverse conditions, you never get there.
I would say that I'm not a big fan of the night dives - at least based on my single experience there, which was at Stetson in higher current and lower vis. I'm nearsighted as heck wearing one of the Hydrooptix wide-angle masks and for that environment the extra field of view is a huge disadvantage, because my dark adaptation was shot immediately by all the dive lights I saw in my peripheral vision. So I saw nothing but absolute black blur and lights, and for that reason and due to an event with another diver that killed some time and got the breathing rate a bit elevated early on, I called the dive early. (I still feel I owe my buddy an apology for that, even though I know it was the right choice for me.)
So to sum up this flipping novel: If you've never dove the ocean before, I'd say it is too soon for you (and by you, I mean the team - both divers). If you've never been in fairly open and deep water before, ditto, skip it until you can get your feet wet there. When you do other dives, even if things are closer, pay serious attention to navigation using compass, kick count, etc (NOT landmarks - I don't care how 'unique' and individual you think a given coral head is when you pass it heading on one bearing - you can't pick it out of the mass when heading past it in the other, without way more than one dive in the same place...its hard to think of it when you see those tiny spots on the map out in the gulf, but the FG banks are HUGE compared to the distance a diver travels on a single dive, so it is different than diving over an isolated chunk of reef in the Keys, Caribbean, etc.) But if you're fit, and you are serious about talking thru the issues and coming up with a coherent plan before you go down, then the dive frequency, rough seas, close quarters, and giant stride are not themselves IMO reasons to not go. Rough seas affect all divers on egress, and experience has little to no bearing on the likelihood of seasickness, either. If you're prone, you're prone...
Would I do it again? Yep, absolutely. Got a voucher burning a hole in my pocket for the Fling again for myself and the wife and I are booked on the Spree for Labor Day weekend this year.
