I agree with ASPHALT ROCKET, definitely get a good quality wool cutting pad and use this for your initial cut.
I would ask them how many coats of clear they sprayed, 3 is usually minimum if they know it's going to be wet-sanded, cut and buff but they may have sprayed more. (cross your fingers).
Some painters will only spray 2 coats but they'll be real heavy coats. The idea being is you want some film-build to work with. It's almost kind of relative at this point as there's no way of knowing how much clear was taken off via wet-sanding.
First thing you want to do is make sure the car is absolutely clean, you don't want any dust or dirt or sand paper grit particles on the car anywhere as the air-current created by your rotating pad can draw particles into your buffing process and cause random circular scratches in the paint.
Next I would do a Test Spot, test out your compound and wool pad combination to a section about a foot squared or so and see how easy or difficult your sanding marks come out. You want 100% of your sanding marks to come out easy, that rarely happens, so you're looking for what percentage of sanding marks come out after say 6-8 section passes with the rotary around 1500 RPM
See what you can do with a just a few passes, if you buff till they are all gone you won't know what percentage are coming out quickly and what percentage are coming out only after lots of buffing.
After you buff your test section inspect the finish carefully for Tracers. I'm assuming this car was hand-sanded using some kind of straight, back and forth wet-sanding technique. What you want is minimal tracers, if you're seeing a majority of sanding marks come out but you're left with a lot of deeper scratches in the paint this is a bad sign. Usually it's safer to re-sand the car with better paper or by machine and then buff out your sanding marks instead of heavy and hard compounding. Wet-sanding is cool as compared to heavy cutting with a rotary buffer.
If you're seeing a lot of tracers you might want to think about re-sanding the major panels using either the 3M or Mirka systems. The body shop will have air-powered DA sanders you can use and make them buy you the sanding discs. (They're expensive)
One thing I know for sure and that is I would rather compound after machine sanding with #4000 grit Mirka Abralon versus compound after #2000 grit hand sanding. #4000 grit Abralon buffs out like a breeze...
Generally speaking, the sooner you can get to buffing the easier the sanding marks will come out so get moving on this project as soon as you can.
Lay down some painters tape on top of any hard body line and then buff up to the taped line, not on top of it.
Also, try to have the car moved to a location where you don't have people sanding bondo or paint next to you as well as grinding, you don't want to fight dirt and dust in the air landing the car. Remember to take some ear plugs, you're going to be running that buffer for 10 to 12 hours a day for a couple of days. (At least I would be but I don't claim to be fast)
Take lots of water and food with you, I never take lunch breaks for stuff like this as it's very time intensive. Eat, drink, get back to work. Safety glasses aren't a bad idea either, over the summer I got a piece of metal in my eye and had to go to the emergency room and have it plucked out. I was wearing safety glasses with eye shields and being careful and it still happened and it really drove home how important my eyesight is to me. (Ouch that hurt!)
Good luck!
