I also use bonnies method... I have strips ( 1/1.5/2/2.5/3) and i have sqs 2x2/2.5/3/3.5/4/4.5/5 and I also have a go so i have Bricks, small and large tumblers, hexis, pretty much any of the geometric Go shapes they made, I will cut my scraps (9inches or smaller) into what appropriate size that scrap best fits.. Once the tub gets full i sew away..
I keep each size in its own sterilite container.. I can then pull what im looking for when needed...