If you are put a one patch with a four patch, I always make my 4 patch first and then cut the one patch to match whatever size it comes out. I still have a hard time get my sewn patches to come out at the right size. They always seem to be just under the correct measurement. I use a scant 1/4 but it doesn't seem to always work out like it should.
Find the smallest block and square up everything else to match. We won't tell that it was supposed to be bigger.