Though I have never used them, I always wondered about using an RC8 and these two with a 2.5 inch moonlite
http://www.teleskop-express.de/shop/...size-sens.html
http://www.teleskop-express.de/shop/...Flattener.html
It is attractive because it would be all threaded, has room for an AO unit if wanted and would hopefully provide a large corrected circle.