After getting several different inputs and thoughts and suggestions on this the decision has been made to send an F8 (18 x 11) to each member who signs up. This is enough fabric to combine with each person's stash to make a 12.5" unfinished block. This makes it affordable and also allows for the bigger group size for the bigger quilt. The swap will be limited to 36 swappers so that no one who joins will feel overwhelmed with the 3 month deadline for the blocks.
I hope this clears up any questions or concerns :-)
Hugs
April