Hi - here's a little suggestion (tho... I'm no expert by any means) I read in one book that if quilted squares that are not prewashed .. your best bet is to iron them with lots o' steam. I've tried this out on fabrics I know will shrink (like flannels) and it really seems to work. If they are precut and made for a wall hanging it probably won't matter. But a hot iron with lots of steam usually will shrink them down to size. (That may not be what you want tho... cuz some fabrics may shrink more than others...) dunno just a suggestion.