ILovetoquilt, I have the same problem. But I have used fun foam, measured inside the hat, and put a piece about 1" wide, all the way around the inside. (I tape it and just put it on my hair, then put hat on. If it fits, I use Goop and glue it insde. If not, I cut another piece, same size, glue them together, then glue into hat. If I want a bit nicer look, I cut a piece of cotton material to fit around the foam, then glue into the hat. I've also used elastic, in wider widths. Anything just to fill up the necessary space. Sometimes the hat will have a ribbon around the inside, I've even slipped foam inside that.