I think it was Kasilofchrisn who did a really nice write-up on a similar technique a couple or three years back. I had ideas that I was going to try his technique and just never got to it but what you're doing here should certainly work ok. This is a cool idea. I've seen foils such as this in Hobby Lobby and Michaels and JoAnns Fabric's crafts sections. Another source might be in woodworkers supply houses where gilding appliques use the thin foils. Pretty nifty trick here!