I drilled and riveted the aft deck. I had a .6 degree twist. I pulled and tweaked for a couple of hours and couldn't get it to settle down after it was clamped. Then. . . I cleco'd on the aft skin. Perfect without any clamps. I had 0.0 at both the spar and the aft deck. I clamped it down and it held 0.0. Drilled and riveted. Van's is not kidding, when you rivet the aft deck, it is locked down. If you had a twist before you riveted it, it is there forever. I was able to squeeze all but ~ 8 rivets. I bought an Avery longeron yoke a month or so ago. Very handy tool to have.