Looking for advice. My first project, a square tool stand with 4 shelves is in progress but can't seem to get the frame and shelves square so it sits flat on the floor (level concrete) with shelves level? First just measured from floor up to each shelf bracket assembly and it was very crooked. Loosened up all the joints and tried using bubble levels to square everything up. Each adjustment seems to undo the previous adjustment. Double checked all the pipe dimensions and they are good. Looking for any possible tips for getting all the joints better aligned?