I work with harsh environment designs all the time and have seen nylon lock nuts fail fairly often. The interior of the car isn't too bad- no solar or solvents, but the temp range is fairly broad and cycles daily. So, no nylon locks on my scoobs if I can avoid it, loc-tite or a different mechanical stop-gap.
You should be able to google the clutch throw adjustment pretty easily. I know I saw it in the tech site, but it doesn't look like I saved that page.
Nice save with the fam in tow.