Today I worked on placing the rear tube frame for the fuselage skin. It went pretty well. My only word of caution is make sure the tube fits correctly inside the fuselage before trimming. I almost screwed up big time. Had I not cut the tubes a little long to begin with, I'd have had to re-make it. I measured the correct length to cut the tubes by shooting a laser "plane" across the top longerons and letting a yardstick dangle from the top of the jig. The laser line showed up exactly at the measurement where I needed to make the cut. I cut them a little long (just in case) and trimmed them a little at a time for a good fit. Trim equally from both sides so you don't end up lop-sided.
Note the dummy tube in front of the frame at the top