If/When I am sewing long pieces together that I am reasonably sure that I cut the same length, I pin each side into halves and then fourths - and then match and pin the sections/sides/seams together - and then I sew "section to section" - this seems to minimize the "creeping" -
I can deal with about 1/8 inch unevenness on one edge - if it's a long seam - but that does not work well on tiny blocks.