I've done quite a few, and used felt front and back. I like felt as it's easy to cut, and doesn't fray. But like you I think sometimes they come out a bit thicker than I would like. I have used satin front felt back, and cotton drill fabric. I guess its a matter of experimenting and deciding what you like. FSL is good for bookmarks, because it's so thin, but there are so many lovely applique designs that I like too. It will be interesting to hear what other cuties have done.
Hi Kay, you can now download the instructions from my web site, so just ignore the pm.