Hi CRO. Let's see if I can put numbers to it. If the center square is 3-1/2" square and you added 1-1/2" strips to all 4 sides your piece would now measure 5-1/2" square There fore needing a 5-1/2" flying geese unit for each size plus the end squares to match the height of the flying geese unit to complete block. Wish I could do a hands on the help you. Your flying geese look to have a shallow "v" that mat be a seam side problem. Sorry
Judy in Phx, AZ