Hi H,
I have had a DSI RC10C for about 5 years and have really only had one successful image (my fault, not the 'scope). A 4 frame mosaic of Omega Cen.
http://www.astrobin.com/full/80259/0/ I haven't used it for 3 years or so since I set it up imaging on a forecasted clear night and went inside for a cuppa. Came out again and it was raining and the primary was like a half-full soup bowl! When I eventually removed the primary mirror, cleaned and very accurately replaced it, I had managed to put it out of collimation. Having no experience there I struggled along until Paul published his work in that area and now I might have finally fixed it. Haven't had a suitable night for > 3 months to test it but here's hoping. One of my favourites, NGC 300, is now rising and it fills my QSI638 perfectly with the RC10C.
Probably my only change, if I had my 'druthers, is to get a CF tube rather than what it currently has. The RC10C seems to require an awful lot of focusing and I would think a CF tube would reduce that.
Cheers