I use Challis too, but I still get the marks - especially on stainless frames. I think any kind of thin substrate under the grip would help, but for $2.50 I'm gonna try those frame savers. I've been meaning to try a set of Aluma-Grips ever since I saw a picture of someone's Deep River Custom with a pair I really liked.Challis. Challis. Challis.
I bought one set of bushings and O rings to try. I now have them on all my 1911s and use their bushing removal tool. Everything else is second best.