I am doing a recover and rebuild on my acro 1 and i plan on installing leading edge plywood. I have been told to make sure the wings are square before the ply goes on. the drag wires were loose when i removed the covering so i knew i would have to sqaure them.i leveled the fuselage and droped plum bobs from the tail post and near the firewall and poped a line for thrust center line,then plum bobed from the wing roots of the lower wing front spar. then poped a line 90deg across the thrust line and lined the wing spars up to it with the drag wires.looked great by eye but when i measured from the tail post to the wing tips it was off by 1 1/2 in. should i square to thrust line center or to the tail post?Edited by: garry c