Quite ok John

Pugo ... You should be a Politician .. or a Ford Workshop Front-counter Manager ..
(but not an English teacher or counsellor)
Your costs assume you already have a torque wrench/gauge, all the tools, and ignore all the other gaskets, then? It's likely to be heat that has damaged the guide seals long-term, not a bit of guide wear.

P.S. The washing line trick is superb, by the way .. you should try it sometime.
You cant lose anything inside, and you could probably put a valve back in if it dropped out (which it cannot)