The ring is for some other esoteric visual / photo thingo if I recall, take it off and put it somewhere safe for when you sell it, until then, forget it.
Sounds like you're having fun, and that's really what it's all about until they pay you to do it
BTW, I didn't have to mod the SW crayford on my f5 newt to get focus, if I recall, it was about 5mm from full in. But also, IRCC, JJJnettie had shortened the OTA to move the mirror up. The alternative is the long mirror screws and Brendan and Co can describe that, I personally never having done it. It sounds like a good method to me.
Yaahh, charge on, mateys!
(I knew you'd like the f5+HEQ5 combo, it's a real winner).
Cheers,