Alex, a cooled camera such as those from ZWO certainly give you more consistent performance throughout the year, and eases calibration.
For OSC, I believe that currently the ASI294MC is the pick of the crop from a sensitivity point of view. It has a comparable sensor size to the 1600 models, and so is more of a square-ish image than Canon/Nikon.
I’d imagine you might get good results if you can nail round stars with 2 minute exposures unguided, but I’m not certain.
Would certainly be overkill for a guide cam
