Caveeagle
Contributor
...With a rashguard you are actually neutral, and your buoyancy doesn't change depending on pressure/depth.
^^ Not true for everyone. Depending on individual BMI. Many people will sink just fine wit only a rash guard.
At the end of the day, you wand as little add on weight as possible. To be as close to neutral as possible at end of your dive ~500psi etc. and have tanks you can get proper fills on for where you are diving.
In Hawaii I have found only AL80 for rentals. Other places I either bring my own steel, or rent LP85/HP100. 85 are great tanks, as long as you can get good fills. Hp100 are ok too, but might be a tad neg if you are already a “sinker”. For many folks who are natural “floaters”, a HP100 is a near perfect tank.
Dual, or redundant floatation bladders should not be necessary if you are not overweight and can swim up your rig.