Drilled 5 #40 pilot holes in each side of the gussetts. Positioned and drilled #40 holes into the cabin frame and side longerons. This required lots of clamping and repositioning of clamps and clecos to get all the holes drilled. The slightly acute angle makes it tough to get to all the holes. Upsized holes to size 20. Ended up using a flexible extension to the drill to get to the inner holes. This was one of those things that looks like it should be easy and quick, but takes more thime than expected.