Gents,
I have a set of the white indiglos and have been trying to find something to "stick" them to the old guage fronts. The guages came with double sticky tape which is pretty sticky and a pain to install. A perfect solution would be a glue that provides long term adhesion, some flexability to counter thermal expansion, and is removable if we want to remove the guage overlays.

A quick update: I have been trying clear silicone. I have tried two different varieties both with no joy. Neither will stick overnight. The good news is that I can peal the "glue" off the guage fronts so that I can get back to the original guages if I want. I will keep working this. I may try rubber cement. Any suggestions will be considered. And certainly if you have found a solution let the rest of us know.