The idea is to find one that FITS YOUR hand. It is not a complex procedure. It is like shoes. You put it on and you can tell if it fits. You find comfort in hanging onto it.
Many guns also have a wide variation of grips available.
The idea it to try as many guns as possible and various grip designs to find the right one. In my case a Browning High-Power is as close to ideal as it gets. The newer double action high capacity guns have huge grips and my small hands don't do well with such guns. That is not the fault of the gun. It is a question of fit.