Looks like a great project! My respect for your drive to do so many things yourself.
I am working on something similar, but I have the advantage some work has been done for me and there is a bit more stuff for sale over here.
I bought this 1992 R80GS with a Siebenrock 1000cc kit and a WP 48mm usd front fork (foto attached).
After that I have put on a mono seat on a self made shortend rear frame, with a smaller battery, a BSM stainless steel exhaust with a good Y-pipe, a UNI open airfilter, an oilcooler, a ring to enlarge the oil pan and self made bash plate instead of the pan, an inversed brake lever at the back, a HE 320mm front brake disk, adaptor plate and caliper.
I am trying to reduce weight everywhere (mainly using the angle grinder).
The dashboard consists only of a Nuvi 510 GPS, the instrument lights and a bycicle speedometer. A second one and a roadbook holder will follow.
The taillight consists of LED's and the front light (classic G/S basic front) has an xenon light.
I am busy refurbishing the carbs, timing chain and rectifier (same as your setup) and I want to mount some subframe for a set of saddle bags (no cases for me). I have an appointment with a suspension specialist because I also want to raise the rear end (so please keep us posted here, the road I want to take is to shorten the bar underneath the swinarm and with that straightening the rear angle of the swingarm) and I am interested in your frame reinforcement drawings.