I try not to have any to minimal variance. Once my blocks are done, I trim them all to the recommended pattern size, sure makes it a lot easier when piecing the top. Very little easing in when I do this important (to me) step. I have also been known to use featherweight interfacing on the back of my blocks too, helps to eliminate the give when piecing the top. I just have to much OCD in me. 🤪