I use a 3 mil, integrated BCD with 4 lb on each side in the front and 2 lb in the back on each side for a total of 12. When it gets really cold I have a 2 mil "jacket" and add an additional 1 lb in each of the front.
I think the fins are the biggest problem but before I go buy anything, I'll try putting the tank lower and the BCD lower and see how that goes. In the past besides not being able to control my position (I'd end up in a diagonal if I just float natural) my back would hurt from constantly arching trying to keep my feet lower.
Thanks for all the info.
What fins are you using? Tusa, by any chance?