A word of caution. Some people have used the wrong type of rod ends on the connections between the stick and the aileron bellcrank. That connection needs to be able to rotate as the stick is pulled back and pushed forward. The correct rod ends have a narrow shoulder. There have been at least two instances where the wide shoulder type rod ends were used and they broke in flight. Both landed safely using rudder alone to bank the plane but it was extremely hairy.
My manual and build photos went with my Model 4 when I sold it, but I still have a few other photos. It means to set the top of the aileron/flap mixer horn at 11.4 or something degrees in relation to the cabin floor. So, level the fuselage, then use an angle finder or smart level to set the mixer horn when rigging the flaperons. That's the aileron/flap mixer horn in the center of the first photo. The small holes in the various parts are where to center the lightening holes if you put them in.
Here's a good story about a man who survived for three weeks after his cabin near Skwentna, Alaska burned down in mid December. https://www.scribd.com/document/442461512/Winter-Fire-Survivor-1-10-2020#from_embed
I'm on the other end of the two stroke primer spectrum. Ran a 670 Ski Doo with primers for 20 years and a Rotax 503 with a snowmobile primer in my kitfox for 10 years. In cold weather a couple shots on the primer the Ski Doo started with one pull and two seconds on the electric starter button the 503 kitfox started first blade. Now, all old Ski Doo drivers know that if you don't shut the fuel valve off when trailering, the needle valves in the carbs will jig, letting fuel through and fill the crankcase with a half a cup of fuel.
I have an Arctic Sparrow adjustable needle set up for a 503. It consists of modified Bing 54 carb tops, cups, slides, and cables with threaded 11K2 needles silver soldered onto the cables. All paperwork and instructions included. The Hacman has made these Arctic Sparrow adjustable carbs kind of obsolete so I would give them to this this fellow if he may want them. This set up was modified by Mike Jacober, who developed the adjustable needle system. If your friend is interested he can have them for the shipping cost. I'm in Ellensburg, WA. They need a good home. I'll get some photos if you're interested. PS. You mentioned he needs slides for a newer style Bing carb. These are 1994 vintage so I'm not sure if these slides will work. I'm not familiar with the newer carbs.
The purpose of leaving the spars full length is to get the proper amount of twist in the wings. A jig is made of a level saw horse under each end of the full length spars with a 1/2 inch block under the tip end of the rear spar. If you are building a short wing...AKA Speedster...you do not install ribs numbers 1 and 2. Rib bay #1 (18 inches) gets cut off. Rib number two is left out along with the drag/antidrag tubes to make room for the fuel tank which also serves the purpose of the drag/anitdrag tubes Photos of the tip end of a left wing. Note the 1/2 block under the rear spar.