If you are adding this as an update to an already flying airplane or an earlier fuselage kit, the diag. stiffener needs to be shortened slightly.
If that is the case you need to get a copy of the retrofit instructions
Nope this is a new build. I did already rivet in the F-1202-N angled stiffener and notice that I should have probably done it the other way around, so I started with the F-1295 first.
With the F-1202 riveted on the F-1295 can't fit level with the holes without going between the skin and the F-1202 stiffener.
I was going to take the F=1202 off and trim it down, test fit both parts and go from there. It's always a pain to undo something, but it won't be the first time