enlarging blocks can be ok, but you have to remember a 4 1/2" unfinished block really needs to be doubled to 8 1/2 unfinished, not 9"...you do not want to double the seam allowances :wink: so you need to take that into consideration on each piece, other wise over all, you will come out too big on your blocks, some more than the others.
Example of doubling block sizes AND the seam allowances:
one 8 1/2" block with 6 pieces will end up smaller than another block that has 9+ pieces in it. There could be an inch difference between the two. A block with 12 pieces could be 2 inches bigger than a block with only 6 pieces to it.