Do know about pulling the diagonals to square things up? Make sure that the holes are large enough to allow sufficient adjustment of the posts and fasten boards around the outside to hold those distances correct Then adjust poles so both diagonal distances are the same. It is easiest to get things close and then fasten one pole securely by backfiling and tamping making sure that the post is vertical. Then check the diagonals again as each post is set. I placed half a bag of dry cement under each post and then the remainder of the bag after placing the post. It will absorb moisure and harden on its own. I nocked the posts near the bottom to help from heaving or floating.