You certainly put in a respectable amount of time on this, Tim....well done.
I've learned something also and will not assume all valve bodies are the same.
Throwing ideas around or simply venting your frustrations are part of what this internet thread thing is all about.
It's always easy to give advice when you're thousands of miles away and not having to do the actual work yourself, but I'm happy to be of some assistance.
......Now about that S10??? and, feel free to add comments about the 660. We don't get that bike in the US but I've always liked it.