Brief Description: Squaring and setting the first bulkhead
If you hadn't noticed, I'm making the fuselage upsidedown, so the vertical channels are perpendicular to the work table.
I used some folded-over duct tape (so it wasn't sticky) to pull the fuselage halves together to the correct 40" wide. The metal ruler on the top was taped in place at one end, and left floating on th other. I would pull on the duct tape "strap" until it was at the correct 40".
Then I used a diagonal duct tape strap to pull the corners together. Measuring diagonally from corner to corner I tweaked the "strap" until both dimensions were equal, making the frame square.
I then set a couple of clamps, and outlined the inside of all the holes where they met the box beam and the cross tie. That way if anything shifted I could see that the outlines had shifted, so I could then move everything back in place.
Used a metal ruler and folded-over (so not sticky) duct tape.
Folded duct tape across the top to hold the fuselage at 40" wide.