Silicone wouldn't be my choice either.I heard of some using it.. I like your teflon tape idea.Not sure if it would stay in place though.. There is no glue to hold it.. I've used Lighter Fluid to remove the glue residue left from electrical tape. I've gotten good results from the electrical tape and will stick with it.This was also recommened by Uncle Mike's (Butler Creek).Sometime back I contacted them seeing if they has a special glue or adhesive to keep the covers on. That's when the electrical tape came into play.

Works for me.

Ruger Redhawk