Thanks for this. I used that method to quickly take my switch out to compare those insulators again. You are right, there is a difference, but it is so small it could probably be measured in microns. I can't imagine that a difference this small fixes anything that the spring loaded GPin couldn't adapt for already.
The bottom of the AW batteries is different from others and the insulating coating is thinner. The spare insulator protects the switch from auto-firing with these batteries and even tenths of millimetre matter