My Sierra installation. These replaced Robart 615s.
RCU would not let me upload pictures, so they are here:
Picture 1 - A. Completed working installation. The Sierras sit more forward than the Robarts so a couple of holes from the Robart installation are showing in each rail.
Picture 2 - The Sierras just barely fit between the leading edge and the spar. The rear air nipple fit through the existing hole in the spar. Had to trim the forward sheeting all the way to the rear of the leading edge.
Picture 3 - A. Trim the channel to the wheelwell just a little on each side. The upper portion of the trim is plastic. Got into just a little balsa at the bottom.
Picture 3 - B. The back of the retract frame didn’t quite clear the spar/shear webbing. I dremeled just a little in that area.
Picture 3 - C. Note the thicker nylon washer between the retract and strut. My wheels (stock) were just barely binding on the front of the wheelwell. Pulled off the strut and installed a very slightly thicker nylon washer (probably from Lowes).
Picture 2 - B. Once I was sure everything would fit and the retract rails were level, I put a thin paste of epoxy/microballs on each rail, put a layer of waxpaper over the retract, set the retract in place and weighted it down. Got a good square retract setting.
Put the wheels in place, hook up the airlines, make sure it works, then drill and install screws one by one.
A degree or so of toe-in with the tail up has worked best for me.