Skywatcher SCT 5" XLT 127/1250 (rebranded Celestron C5) finderscope base

[rofus]

Hi all,

I'm about to buy a Skywatcher SCT 5" XLT 127/1250 (basically a rebranded Celestron C5 - see pic attached even if that's bigger one), but I'll need to replace the finderscope with my Orion that needs a dovetail base (I have it as my other telescope already had one):

http://www.telescope.com/Orion-Magnificent-Mini-AutoGuider-Package/p/99631.uts

Anyone knows if I'll be able to simply unscrew the old finderscope base (same as in Celestron C5 and bigger ones) with that 'universal' base I have in my Orion Magnificient package? Or do I need to buy another one like this?

http://www.amazon.co.uk/Orion-Schmidt-Cassegrain-Finder-Scope-Base/dp/B0000XMY4C(that someone says doesn't fit a C5, someone else says it does with a bit of fiddling)

Also at the moment I use my Nikon D90 on a 2" focuser (but I also have the 1.25" adapter I used previously), will this fit on the Celestron C5? Can I fit a 2" or I need to go with the 1.25" ?

Thanks!