I had the same problem w their steel panels. I shot my grade benchmark and then dug out the total 42"all the way across thru the overdig. I went back and installed the half of pool of the deep end and got it rly close my panels were all same size so I squared it from seams of panels and I used 2x4s at the base of walls across pool to keep it perfect distance. I rebar pinned the walls and the supports to keep it close, you DONT need to worry too much about top of wall panels right now, just keep them close and worry about the bottom, pull tape from lowest point of wall to square it. If you are saying that one end is longer than the other and you are super close on square a panel is out of size, if you tape each one from seams you will find some differences, I had some panels that were taller by 1/4" than others and a few that were 1/8" heavy in length. I ended up 1/4" out of square and 1/4" long on one wall but its close enuff liner will fit even with an inch out. DIYíng the pool we nitpick everything, you think pool companies spend that much time getting it perfect? no way they get it close and they know what they can deal with and move on time is money to them. Im about to do my vermiculite Ive been rained out for almost 3 weeks I ended up getting a harbor freight 20x40 tarp and built goalpost across middle and made a roof over the pool and it helped alot or you can do like you did and lay it down and put a vertical float sump pump in it and let it be a temp liner to help dry it. As long as your long and short walls are straight when you are ready for the collar pour it wont show being out. Also stake the panels and use 2x4s as braces the short way and stake the inside walls I had hair movements from the concrete pour if I hadnt done that my walls would have been messed after concrete