what is the "preferred" method for doing this type of repair to foils?
Thicken gel with colloidial (fumed) silica - Cab-o-sil or WEST 407.
It will make the repair a bit harder than the surrounding gel, so you need to be careful when finishing it off (don't get "dishes" in the surface).
Try to remove as much extra material as you can while the repair is uncured.
