Regarding chasing the threads for the tee handle in the head light castings, the threads in mine were rusty and clogged, so before buying a tap to chase the threads I tried using a Dremel tool and small wire wheel to clean them. After a good brushing and with plenty of WD-40, I was able to thread the brass fittings into the castings without any problems. The threads on the fittings looked coarser than 20 TPI, so out of curiosity I measured the thread pitch and mine are actually 18 TPI. Maybe they made two different flavors? Or (more likely) mine are prototypes and the only ones one the planet with odd-pitch threads. Anyhow, confirm the thread pitch before running a tap into it.