I had been looking into that, too, and here's what I found on the Accuquilt site for the 8.5: rag die:
Cut Size 8 1/2"W x 8 1/2"H (22 cm x 22 cm) rag square with 3/4"L x 1/4"W (2 cm x 1 cm) fringe
Finished Size 6 1/2"W x 6 1/2"H (17 cm x 17 cm) rag square