Driled the upper cabin frame mounting points (9 holes each side). Drilled to #30 then #20.
Removed cabin frame to file an area that was pinching a rivet in the frame.
Was sent on a wild goose chase looking for part C75-F12-4, a gusset shown in the builder's guide. It was unclear whether another gusset, N1-2, was suppoied to mount on the front or rear of the lower cabin frame point where it meets the fwd fuselage.
Turns out my kit didn't have C75-F12-4 (nor was it supposed to have it).
Have contacted Zenith just to make sure of where the gusset SHOULD go.