I'm sure it worked well for you but it sounds like a recipe for disaster for a bunch of recreational boaters and divers who have never raised a sunken vessel before.
There are lots of imaginative ways to raise a boat. The first one I did was done by putting two kapok lifejackets on the top of the mast of a thirty foot wooden cutter that was in about forty feet of water. A diver went down and unbolted the keel and the wood boat floated up on her own and rolled over on her side with the lifejackets on the mast holding her from rolling upside down. We hammered plugs into the holes for the keelbolts and slide the mast out before pumping her dry and towing her to Nortonís Shipyard in East Greenwich RI. The keel came along later after we put a dinghy over it and lifted the keel with a come-along on a sling under the dingy. It was the worldís most stable dinghy with that keel hanging under it.
I think raising a boat while you are out of the water and above it is much safer then having drums pop up to the surface unexpectedly because itís so hard to secure them. Yes air bags are nice and safe but I donít think this group will find any so this is my suggestion based on real experience instead of just guessing about what might work. If you rig everything using a bit of common sense (something thatís not so common today) you will be fine. Moving great weights is easy if you think about it and go slow. I just put a 3,800 pound Brown & Sharp milling machine into storage yesterday. It was moved entirely by using toe-jacks, pipe rollers, Johnson bars and a strong back. The hardest part of the job was planning it.
All the best,