The wads should only be used on flat based conicals, never hollow based conicals. The wads are meant to protect the base of the conical from the heat of the powder charge and reduce leading as it was explained to me. I use them when I shoot REAL concials but never when shooting ball-et for instance.

Another use of the wonderwads is when shooting patched roundball. It will help seal the load and protect the patch when fired. Actually the patches look almost (and I have done it) like you could shoot them over again.