for the skywatcher. I have a 10" 1200mm skywatcher dob with tube rings fitted and mounted to a eq pier. The optics are excellent and the mirror is factory set for camera (prime) focus. I also have an older 10" f4.5 meade starfinder, but the optics are no where near as good as the skywatcher.
As for steel tubes v/s carbon, I have an old 8" f6 newt with a fibre glass tube and it does not have the half the dew problems that I get with the 10" steel tube.
Rick