Are you aware of any physiology requirements linked to g onset?
Now your question is a little easier to understand.
There are two situations of interest regarding G and pilot response
(a) low onset rate - typical situation where the pilot at some G (depending on individual response, technique etc) greys out and then, at a higher G, blacks out. Recovery with G reduction is rapid and the outcome (generally) fine.
(b) high onset rate - the pilot response is different and blacking out occurs rapidly. More importantly, recovery with G reduction is prolonged and the pilot, functionally, may be incapacitated for some time .. with undesirable effects. As I recall, the Blue Angels mishap in 2007 (where a member pulled very aggressively into a rejoin) was put down to this effect.
Generally referred to as G-LOC (G-induced loss of conciousness) or some similar expression.
Any number of articles on the net, one
here and another
here.