SCT Finder Shoe Screw Size

[Stratis]

I have three SCTs in the stable, a SkyWatcher 127XLT (so basically a blue-tube C5), a 2014 orange-tube 8SE OTA, and most recently a reasonably-new 6SE OTA.

All three are Synta-era XLT-coated.

Unfortunately between them I am missing several mounting screws that previous owners have lost over the years, so adding finder shoes is really difficult.

Does anyone know the appropriate finder shoe screw thread for these Synta OTAs? 

There's a post on here which states that the old USA models used an Imperial thread, but I feel like the chances of a Chinese manufacturer using Imperial sizing is very, very low.

Please help if anyone knows, or if anyone has any of these scopes and a way of determining thread pitch and screw size

[Cosmic Geoff]

I have noted: Celestron C8 rim screws rear UNC 8-32, 5/16"

front UNC 10-24, 5/16"

If attaching some finder shoes you will need to order longer screws - try ebay.