I noticed that the ASI290MM-Mini guide camera is no longer listed in the on-line catalog. The loss of that camera with its small pixel size (2.9) leaves a gap in the guide camera line up. IMO.
While the surface specs of the remaining cameras look good, they are NOT imaging cameras and don't typically need high frame rates/etc. What a guide camera must have is a arc-sec/pixel resolution with the guide method used (guide scope or OAG) that is roughly equal to or (preferably) slightly better (smaller) than that of the imaging train.
The reason is simple, you want the guide system to be able to see at least of much of the apparent movement as the imaging train. Even better is when the guide train can see movement that the imaging train cannot. Providing the mount is capable, this setup allows the guide system to have a "so so" or even moderately bad seeing night and still have excellent guiding from the perspective of the imaging train.
If the imaging train can see movement that the guide train cannot, then even an excellent night from the guide train's perspective result in bad frames/mishapen stars in the imaging train.
My current setup with the 2900MM/OAG-L and a 2600MM imaging camera result in a 1.09"/px for the guide train and 1.41"/px for the imaging train. I almost never have a bad frame from guiding unless something has gone wrong (fog/clouds/etc.) Conversely, same setup using a guide scope resulted in a 1.89"/px with the 1.41"/px for imaging. There was always a frame or too lost due to oblong stars. The "new" 220MM Minu with its 4u pixel size would put my guide setup back to have a poorer pixel resolution than my imaging train, even though not as course as that with an external guidescope. This, IMO, is a step backwards.
YMMV
