A normal floater is probably someone who doesn't breath normally in water. That is, a floater is someone who probably breathes in full deep breaths and never fully exhales. A full or near full exhale is normal breathing. A full inhale is not normal breathing.Its a balance youll have to estimate and Id go a bit heavy so you can hold a safetystop at 20 ft with 5 - 700psi in your tank. Idealy, with a full breath holding in your lungs, you should be able to float at eye level with 700psi!
When don't exhale fully you are more bouyant and you want to breath more because you never fully exhale the dead air rich with CO2.
The downside is higher air consumption which means less bottom time. Bottom time is why we dive.
Even though I'm a NB after listening to my brother with 30+ years experience I've been able to get my air consumption below .4cuft/min. In other words I use a little more air than HALF the air of the average diver, which means almost twice as much bottom for the same air tank and boat ride. When the pack is up in 30 min I might be 45-50 min, and have more reserve in my tank.