measured a bunch, then drilled the slider rail to the top of the fuselage in two places per instructions. Went to install the allthread to the front end and discovered that I had installed a rivet in the bulkhead frame at the location it's supposed to use. Drilled out that rivet, upsized the hole and installed allthread per print. At some point during this whole process, the left aft corner of the frame has sprung out about 1/8" so that it's no longer recessed from the edge of the fuselage the requisite 1/16", but is sticking out by about that same amount. It's a complete freaking mystery to me how that could happen, but tomorrow I think I'll get out the C-clamps and wooden blocks and try to beat this back into submission again. I'll have to be careful since the tracks and rail are now drilled to the fuselage. everything else is still good, and the frame retracts with just light finger pressure, Sweet!