Drilled the forward top skin F-821PP, baggage door support F-821BPP and firewall. Marked the lengthwise centerline of all three, aligned them and made sure the skin was even on each side. Began drilling in the center and used cleco clamps between each rivet to spread the skin out evenly on each side. Nice and tight, no gaps. Tomorrow I will do the same with the second bulkhead F-866. I may insert a few keeper rivets on the baggage door support and the bulkhead to keep them aligned while I force the bulkhead into the proper arrangement. I will tape the skin down so it’s even on each side. I drew a line on each side skin centered on the rivets and when those show through the top skin holes I’ll know it’s properly aligned left to right. At least that’s the plan. I tried it with tape today but pushing the bulkhead into place made the F-866 and F-821BPP come out of alignment.