Been there, done that. You can starch after cutting, but you have to be very careful because you are wetting the fabric again. Here's what I do. Use either canned spray starch, or a mix you've made and put it in a spray bottle with a wide spray setting (I have one gardeners use). Cover the ironing board with a towel and place the squares on it. Spritz each until damp and LET DRY or at least on the verge of being dry. Use the iron and PRESS (not iron) each square until dry. Put the iron straight down on each square and avoid the temptation to squiggle it around. Do this until each square is completely dry and can be safely moved. i make sure they are cool. Sounds like a lot of hassle but it goes pretty fast and saves me a ton of frustration. The caveat here is that if they have been stretched too far out of square this helps but doesn't correct the problem, so I cut them again and make a smaller quilt or add more squares to the quilt at the newly cut sq. size (i.e. from 6" to say 5-1'2")