Hello Peter,
both cameras a nice cameras with an advantage to asi2600mc pro. This one has a higher resolution and I think is newer model than the asi533mc.
But...I would recommend to take another asi camera - the asi294mc pro. This camera has[b] [/b]
4.63 um pixel size[b] [/b]and does a nice job too.
The pixel size is important for longer telescopes like the C8. As Jay already have mentioned the guiding with an asi2600mc por camera must be very very accurate and you risk more troubles then fun....even it is for sure possible to use it with a C8.
At astrotools
https://astronomy.tools/calculators/ccd_suitability you see the differents, if you will check ccd_suitability tool.
I have a C8 and use a starizona 0,63 reducer togehter with my asi294mc pro and it works very well.
wish you a lot of fun with your C8 and CS
Christian
[b] [/b]