The method I was going to use for checking for square with regards to this thread (was gonna do it just for fun) would be to simply hot glue 4 blocks to the extreme corners of my spoil board and then do a outside profile cut as large as I could reach (like 60.5x100.5) and then either use a tape and hook on the corners for diagonals or fashion a simple shop made hook rule from scraps that could get me close enough to read corner to corner with a set of digital calipers. I wouldnt really care what the diagonal length dimension was just that they were as close to each other as possible.

Was a pretty fun post to read and see David comeout the back side with some major improvement.