I don't know much about compressor stats TBH, I know it stated you need at least a 3hp compressor to use it effectively. Mine is 12hp I think, but that's about all I know without looking.

I think most wheels would fit, but you might struggle with the larger alloys as it leaves little room to manouvre. I got 15 inch van wheel to do without much of an issue. It didn't take too long to do the wheel, but obviously if you were refurbing wheels as a business, you'd want something bigger that could do the job quicker, but for personal use I've found it fine.

You can use all types and grades of blast media, but I generally use a medium black grit which I bought from Frost.