Today I made good progress on the rear seat throttle installation. I began by continuing to enlarge the holes in the bulkheads where the throttle pushrod passes through. This is a repetitive process -- you have to file the holes a bit, test-fit the front-seat throttle, remove everything, file a bit more, etc.
When it looked like I was getting pretty close to the right dimensions for all the holes, I fitted the rear seat throttle assembly, the pushrod, and finally the front-seat throttle quadrant. After hooking them up, I played with my new moving parts for a bit, noting where a few more slight adjustments need to be made. One of these is the rear throttle arm slot -- it needs to be slightly lengthened at the forward end, because it hits the forward stop at the same time as the front throttle. I want to make sure the front throttle hits its stops first. I also want to widen the aft throttle arm slot slightly, so more of the inboard UHMW strip is exposed. As the strip wears, I don't want the throttle arm to begin scraping on the edge of the slot.
I finished up by fitting the left vertical channel cap, marking it, and notching it for the pushrod.