For what my 2c is worth, I had an RC8 (FL 1500mm) and it was challenging to collimate, and fairly slow at f8. Paul (Discoduck) on the other hand gets consistently spectacular images from dark sites with his finely tuned RC8.
My former f4 10" newt on the other hand was a delightful light bucket that really sucked in those photons! With the paracoor the FL was 1148mm.
Contributors here on IIS like Lee Borsboom have done spectacular galaxy images with a beast such as this, but under darker skies.
Kevin (Kosborn) uses a 10" f5 Newt very well on an EQ6 too, his FL is a tad longer at 1270mm.
So yes, seeing is a big factor, and a road trip to LMDSS can help with that!
