Cajun I cut my pieces the size you indicated but could not get the middle to fit. I tried a few times. So I sewed the outside together (as if the middle was in there, aligned on the outer edges) and find my middle square would need to be 2.5" to fit. Also, my finished block would only be 11 1/4". Was I supposed to figure out the larger HST squares before I cut them?
btw I only use the 1/4" specialty foot, I never attempt to do a "scant" measure, if that matters.