Personally, I've found the large focuser knob on the C11 perfectly adequate for visual and planetary work.
For DSO...note the mirror locks only exist on the Edge HD series, not the conventional SCT/XLT series.
There is a technique with Celestron SCTs whereby your final focuser knob movement should be anti-clockwise. This apparently takes advantage of gravity and leave the mirror in a settled position. Note that for large changes in pointing direction, it may be worth checking your focus again until you observe how much shift you may or may not have. It varies from scope to scope (often due to distribution of the grease on the baffle tube) and has no bearing on the optical quality of the scope.
FWIW, a C11 is not a particularly large tube...when compared with, say, a 12" Dobsonian