Aren't all rotaries gear driven and thus does not have the ability to slow down with a load? A clutch would accomplish this, but I don't know of any rotaries that have this and if even needed.
Are you speaking about the speed dial which is normally 1-6? If so, I wouldn't want to polish without it. Also a must have is a variable locking trigger.
I have a 65" Sony with a Sony sound bar with a sub woofer and the difference with and without the sound bar is like night and day. Even without music, there's a huge difference in the sound. A musical program is awesome.
Is the car black by any chance? I would not use a polish removal towel to do a final wipe. Polishes have abrasives and not easy to completely wash out. I would keep finishing towels separately.