also if you are planning on using an off axis guider in the future (and a dslr - or similar camera that has a large sensor to adapter distance) then you might consider a coma corrector with extra setback distance such as the baader Rowe Coma Corrector (55mm vs 91.5mm)
http://www.teleskop-express.de/shop/...-distance.html
makes it easier to fit things like filter wheels OAGs etc between camera and CC. perhaps a bit more of a future proofing option.
cheers