If i were doing it - i would first add borders to the panel to make it 35 1/2 x 50 1/2. You could use your 6" squares...cut down to 5 1/2 each....for a 7 squares x 10 squares + 4 corner squares. Or....make it 36 1/2 x 52 1/2 ....then use your 5" squares cut down to 4 1/2".....for 9 squares x 13 squares + 4 corner squares. If you use some graph paper it will be easier to see.....i'm old school...don't have the computer program to do this. Hope this helps.