Splash, I just wanted to clear up something--not a flame at all, I just think we're saying the same thing in different ways.
I was responding to the statement in your original post that said: "I'm not trying to discourage you in anyway by saying this, but be informed that a lot of Dive Operators will not allow an OW diver to make Drift Dives." But your second post was more detailed and I agree with a lot of the points you make.
However I don't know of a single dive op in Coz that caters "exclusively" to experienced divers--they'd go out of business. There are dive ops who cater more to advanced divers with larger tanks, more trips to advanced dive sites, etc, and yes, newbies aren't allowed on these trips. But there are many kinds of dive ops in Coz:
The large ones with multiple boats so they can have a boat of experienced and another boat of inexperienced divers.
The smaller ones with only one boat but tailor the dives to meet all experience levels, like the advanced divers do one part of a reef and the beginners another.
Then there are the cattle boats, that lump everyone together, everyone dives the same profile and the same site and that's that.
Notice I'm not naming specific shops on any of these but I'm sure everyone reading this is coming up with their own examples.
The point I was trying to make in my post was that the dive ops down there won't turn away a diver from drift diving just because he only has an open water cert--all the dives down there are drift dives. Yes, a good dive op will not let inexperienced divers dive certain advanced sites, like Punta Sur, Maracaibo or the northern sites, but they won't turn away an open water student for a "drift dive"--they'll just take them to one of the more "beginner" sites. And they can and will negate a dive site based on the currents that day--the currents change as quickly as a rainstorm down there comes and goes, so the DM generally doesn't know if a site is diveable until he jumps in the water to test the current. The dive ops WILL check C-cards, log books and have you fill out paperwork attesting to your experience level before they take you out. Then most dive shops will group divers according to experience level and choose the dive site accordingly. But the dive ops find all this out in advance--it's not like they'll book a dive trip for him without finding out his experience level. Yes I am generalizing, but if they don't check you out before they allow you on the boat you shouldn't be diving with them anyway! Plus, if one dive op doesn't have a trip appropriate for his experience level, then there are over 100 others to choose from.
Basically 2 Bar, Splash has some good advice--talk to the dive op, ask questions and find out all this stuff before you ever step on the dive boat. Your friends are DM's and obviously more experienced divers, so I hope they use some sense and don't try to push you into doing dives that you are not ready for, even if you think you are. Back to your original question, I really don't think you'll have a problem drift diving, but choose your dive op wisely, be honest about your diving experience, voice any concerns and they will work with you. You'll have to make sure to post a trip report when you get back and let us know how it went!