Negative buoyancy - weights - how to measure what would work best .

[jestersdead]

Ive seen divers gracefully dive without fins and not struggle to fight the natural buoyancy of salt water. What gives. - i get they are part fish but still how so effortless.
Now these are shallow dives and i know they go in with half lungs full which again is mindblowing but do wet suits help in going under. Also i feel like wiehts is the answer

 

[J Campbell]

I've noticed this also. Different people have have different buoyancy. For example a skinny person with small lungs will probably sink easily doing an FRC dive - while another skinny person of the same height but with huge lungs might float doing an FRC. The difference being that a big lung person will have more air even at his "personal FRC". Also a person with alot of body fat will probably float easier. And then there is the thickness of a wet suit and the depth of the dive.
Also, no wet suit I ever saw "helped going under" - indeed the buoyancy of wetsuits is a problem.