Well John I have the RC10 CF, moonlite and STL6303 running on my field G11. Lifting the tube is about as heavy as I would want to lift. I also have the CCDT67 which doesn't fully handle the 6303 sensor size. So I tend not to use it. The moonlite handles the weight fairly well (using the focus motor and locked shaft) and I have not noticed any great focus shift over several hours, but then my imaging "radar" may not be switched on as intensely as other imagers.
Ted