After cutting my pins on the end board, I stood the top board on end and made it flush to locate the knife wall for the dovetail. I made a small knife mark at each end but when I put my square on them (using it on the reference edge like a good boy) the two knife marks didn’t quite line up ( off maybe the thickness of a pencil line). The end of my pin board is dead square to the reference edge so I suppose my top board isn’t quite the same thickness from one side to the other. My question is, should I use my square to mark a line that splits the difference, or use a straight edge to make the knife wall between those two marks, or try to adjust the thickness of the top board? I would think that hand planed boards would often not be exactly the same thickness from one side to the other on a board that is almost 8 inches wide. I feel fortunate that I was able to get it within a pencil line.