diy stand issue

A year ago I made my stand for a 75 it came out almost perfect the tank sat on the stand level. So the last few weeks I built another for a 20 h tank. The top of this one did not come out no were near as good as the first one. Part of the tank isn't sitting flush to the stand. It's a small amount about a 1/16 of a inch. I slid my debit card under it and it got stuck on the numbers on my card. I measured from the bottom of the stand on about 6 different points I have 32.5 in almost every spot and a 16th less in 1 or 2 corners. I have it full of water outside for the night for a leak test and to see if it will lay on the stand right. Should I add a piece of 1/4 foam. It's so close I hate to take it apart but don't want it to break either