I think everything has probably already been hashed out by people more experienced than I in the 10 pages of this thread (didn't actually read them) so I'll just relate my experience.
The number one thing I discovered for making buoyancy and absolutely maneuverability total cake was to take all the overpriced gimmiky recreational crap the LDS pushed on me and throw it as far away as possible.
With a back plate and wing and tech fins I was FINALLY able to get all the extra drag and bulk and imbalances out and get things distributed properly and streamlined.
With tech fins that had zero fancy features and were nice and rigid I turned flopping around into being able to maneuver any way I want including backwards. Use the appropriate fins to balance out your legs. If you are head heavy get heavy fins, if you are foot heavy get these:
www.deep6gear.com
They are what I bought for tropical trips because otherwise with a shorty wetsuit I had to put my feet in the stowed position (90 degrees at knees) any time I wasn't swimming or the heavy fins that are perfect with my full 7/5 hyperstretch wetsuit would drag me down by the stern.
I forgot to see what kind of diving you do, but I have a full 7/5 hyperstretch wetsuit, two different thicknesses of hyperstretch gloves, and a somewhat thinner hyperstretch hood.
When I started, the morons at the LDS had me in a non stretchy farmer john (whatever they call the double layer monsrosity) and I ALWAYS had trapped air and massive buoyancy swings due to the acres of overly thick neoprene I was wearing. The less poof you have to compress and create swings, the less you need to fight to keep level. Spending the extra on the stretchy stuff was night and day better for comfort and the ability to move my body.
Having been trained in the frozen north, when I finally went tropical diving I realized how utterly miserable neoprene makes diving. Its basically the reason you need all the weights in the first place and makes it ten times harder to do anything.
I actually used a rubber weight belt so it doesn't flop at depth with wetsuit compression but still feels nice at the surface, and only put enough weight on it to be able to swim up with no BCD. That allowed for me to stash weight all over for balance and you don't rocket to the surface if you had to ditch because all your weight was stupidly on one item.
Don't bother with a class. Once you are properly streamlined head to foot and side to side, have no trapped air, and have enough weight so that you aren't getting sucked to the surface at the end of your dive (I like to be a few pounds heavy) all it takes is practice, not training.
Anything you need to learn is already online.
If I had my way recreational gear would all be thrown away and everyone would use tech gear. It's not just for experts, its chosen by experts because it simply does EVERYTHING better and rather comically usually costs less than the name brand crap with the useless features and styles they sell to rich beginners.