Page 29-12 has you rivet about 1/3 of the holes in two ribs, 3/4 of the holes in one stiffener, and a handful of holes in the side plate and upper drag fitting to the side skin before putting the skin on the fuselage. Is there a reason for this? It seems like back-riveting would be the way to do it but I have had much better results riveting things in place rather than backriveting.