I've been giving some thought to the rubber parts needed to rebuild the metering/hold-off valve. The challenge is that the cap and the main seal appear to be unique to these valves and I can't find a supplier who has them. That means they'll have to be custom made. I have a quote from one manufacturer who needs $2100 for "shared" tooling and $4800 for tooling I'd own, but both options mean that I'd have to sell a lot of seals before I could cover my costs - and that's just for the seal. The cap costs would probably be similar. If anyone knows of a less expense way to produce custom rubber seals please clue me in!

Thanks for the positive feedback, too. I aim to please!