Another tip I'd like to offer: referencing Eddie's very excellent tutorial on Cathedral Windows where it shows sewing one side of the square, leaving a 2" opening in the middle of it to then turn it right side out & poking the corners out, then pressing it into a square and then meeting the corners in the center to make a smaller square:
I got the square to that same stage by just meeting the corners in the center & pressing, then meeting the corners in the center again & pressing.
That seemed to make forming the squares go faster, for me.
Just FYI, in case anyone wants to try it.
Again, excellent tutorial, Eddie. Also your tutorial on scalloped borders is one I bookmarked & will be using.