I was a little hesitant to drill the gussets without the skin because the bulkeads are so "floppy". Vans support said either line them up with a straight edge to drill (which is the approach I took), or drill them later. The plans say to locate, drill, and rivet anytime.
So I did have a little problem with the F-707 bulkhead. The gussets, now riveted in, pushed the bulkhead further forward then the skin line holes. The right side was a little worse then the left. With a litte "persuading" of the thin bulkhead sheetmetal I was able to adjust the bulkhead enough to get the hole lined up. When the forward skin was added the F-706 bulkhead didn't have this same issue.
Bulkhead flange out of place
This one too
Aft most skin on and drilled minus the j-stringers
