First use of a friend to help set the last few rivets in the middle of the lower fuselage to seat ribs to skin process, just could not reach far enough to have enough control over the gun and buckling bar simultaneously, Also should have read ahead a little as it was a pain to rivet the gear brace brackets to the inner rib because the holes were slightly undersized for the blind rivets, so what I though would take 30 minutes, ended up taking 2 hours in total.