I had the Reefmaster 35mm, then upgraded it with the same flash, then replaced the whole thing with a digital set later on.
The 35mm Reefmaster is worth about $25-$35 bucks because digital has just taken over. Maybe work $40+ if it has the Pelican hard case. (check ebay).
Based on all this, my suggestion to you is to put the $$$ into a digital set or see if you can buy a "used" SL960 flash. You can justifty the extra digital expense easily with the costs of film and developing alone. (especially if you get double prints) If you go used, Ebay might be your friend. There is a SL960 on ebay "right now" going for $50 bucks with about 1day left in bidding.
The other good thing about the digital instead of the 35mm is that you don't have to worry about changing rolls between dives or having enough "film" left on a roll to take pics of what you want. Since you also tend to shoot a lot of pics that aren't great and otherwise hit the trash bucket, this is a much more cost effective way of doing it instead of buying film and paying for processing. Being able to "instantly view" the pics that night on your laptop will also let you know how they turn out while you are still on your trip. this is great for photo troubleshooting.
The good news is that you can always use the SL960 on a digital reefmaster if you buy it. the only difference is a slight size difference in the flash "guard" that deflects the flash from the camera upwards.
You won't need the Boyancy control weight with the flash.
I bought the flash link last year, but haven't used it yet. Bought it because my flash was not always firing when moved in "odd bends" from the camera.
I've got the 3x lens and it's nice for small stuff. I don't see a need much for the 8x or 16x unless you're going to take pics of "really small stuff"
The wide angle lens (about $79) is really nice if you've got to take a pic of a large object but can't do the human-zoom in lower vis. Remember that your color changes the farther you are away from an object, so "backing up" away from a larger object means that you loose color. The wide angle lens helps you "stay close" to the object and both get better color and also if in lower vis, help keep from causing vis problems based on distance. If you get the wide angle lens, get the "lens docking station" that keeps it from bouncing around (and getting scratched).
hope all that helps.
-Mike