Will grip heaters work and survive if placed between grip puppies and the grips? I presume they'll heat just fine since the original grips will act as an insulator and stop the bars from acting as a heat sink. Will it be too much and cause the elements to burn out though? I'm thinking of doing this in to; 1. be lazy and 2. maybe the grips will be warmer without that double layer of grips/puppies.
You can do it. Sometimes however the heating element will scorch both the grip puppies as well as the grips. Not all the way through, but enough meltage to cause all 3 layers to be one. Use cheap grips under em if you have expensive OEM grips.