I'm lucky enough to have a bench polisher (it's pretty powerful).
A bench grinder can do the job fine.
I've quite a few different mops for different steels.
At the moment I've been using stainless so I use compounds designed for that.
A quick internet search should turn up quite a lot of suppliers.
A word of caution, don't go for the cheapest mops, buy better and you won't have to go to the trouble of truing them up.
A bumpy mop is worse than no mop.
Also, they are often regarded as the most dangerous tool in the workshop.
They can do permanent damage.
Take care.