..."Next up is deciding if the original non schneurle ported Enya 60 is what I want to trust or do I try something else and have some reliability built into flying a classic antique."...

Personally, I'd be running that old Enya - - with half-again the amount of castor in the fuel (which is NOT going to help keep her bright and shiny) AT LEAST once, and probably until the engine dies. Enya's are strong, reliable, just plain fun and I don't think (with a decent 're-break-in") it'll give you any issues at all.

And, even if she did eventually fail in the air, everything I've ever heard about the Zlin says it's a pretty good dead-stick glider. You're not going to lose it.
D