If you are thinking of changing your guide camera, a mono version will be better than colour as it will be that much more sensitive without the Bayer Matrix. Just been scouring the pre-owned pages of Telescope House website and have come across a secondhand Starlight Xpress Lodestar if you are interested,works well with the Alpy.
https://www.telescopehouse.com/offers/preowned/preowned-starlight-xpress-lodestar.html
Regards
Alun