My opinion is the buoyancy of a person is very individualized and the only way to get it right is with experimentation. Weight suit thickness and fat % are larger factors than weight and height of a person.
I think the most important goal a person should strive for is positive buoyancy at the surface with a full exhale. This may not be achievable if your diving is shallow water and need to neutral to lay on the bottom, but in this case you need to recognize it and try to compensate, like don’t push your bottom time as long or try to buddy dive with competent diver that will stay with you.
What I do and know some others do too, is when we feel we have pushed it, we lay back on our backs at the surface, even if we have a spotter. It takes about 10 to 20 seconds from the first breath for the O2 to reach your brain. This means you’re lowest O2% reaching the brain is going to happen after you surface and take the first breath. Getting on the back is a precautionary measure that makes sense. A good friend lost his speargun when he passed out on his back, but kept his life. If you have a spotter it puts you in the proper position for him to hold you while you regain consciousness. If he has to turn you from a face down position, he may save your life, but the changes of breathing in water are increased, which means you may be recovering in the hospital instead of diving the next day.
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