Designing the Quilts

OK, so Mom's cut all the strips into blocks and now she is playing with them, designing quilts.

There are 21 different fabrics, cut into over 500 pieces. With all that selection, it should be easy, right?
Uh, no.

If Mom uses every single piece, she could make 24 quilts, but she says that won't happen. For one thing she just found a strip that was cut wrong, meaning each of the nine blocks from that strip is unusable. Oops. Make that 23 quilts. Maybe.