I love stack and whack! Yes pin lots and make sure your pin is through the fabric at the same spot on each level. So you find a point on your top sheet and than make sure your pin goes through exactly on the other layers. Same as when you cut your fabrics. Find that one spot there your repeat will end and than cut your repeat. Than carry on making sure you are cutting at the same point each time. I truly agree with cutting your fabric in half length wise as it makes it easier to line up your repeats. Once you make that first cut you will feel better as I know I was scared Sh_tless. But it was easy after I got started.