The a6000 is listed as supported on this ASCOM driver. I got started with an a7II using this same driver though I was using NINA rather than SharpCap. It worked flawlessly for me.
https://github.com/dougforpres/ASCOM...ported-Cameras
To answer your question your a6000's APS-C is far better suited to DSO than the 1" sensor in the 585mc. The FOV on that camera with a 1000mm focal lenght scope would be extremely tight.
What I reccomend is downloading Stellarium and entering the details of all the sensors, scopes and reducers/extenders you want to compare. You can then simulate the framing of various target's you're interested in imaging.