My point, apart from the point re astro cameras, with your cams and current lens with a good mount and any old guide scope you will get fantastic widefields. I used only an eq5 and for widefield it can run unguided for 45 mins. Using a scope at f5 sees only 150 to 200 seconds of decent tracking.. look into periodic error regards mounts if you have not already. I would be experimenting there first up the shorter f/l's to start there will be less frustration with tracking. I think the tracking (hence mount efficiency) is the first thing to get aquainted with.. anyways a bad decision is better than no decision or indecision and any of your opions would not be bad. I though similar about noise but I expect there is a reason people spend big bucks on cooled cams.. I just recon you will want better than you even have now ...happens to most people in this game
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Good luck
alex