If I understand correctly, you're alternating plain squares with 4-patches. If the plain squares finish at 4", then the 4-patch pieces need to finish at 2", so they would be cut at 2.5". However if the plain squares are cut at 4" and therefore finish at 3.5", then the 4-patch pieces need to finish at 1.75", so they would be cut at 2.25". Hope this helps.