I think you're gonna really like the Porter Cable 7424. I'm not expert, mine just came last Friday. On Saturday, I washed, clayed and 'polished' my new Rendezvous with Meguiars NXT. There's only a slight learning curve and the results were very, very good.
It sounds like your finish needs more work. I'd suggest you start with a really (Clayed) clean surface. Use a different pad for the polishing than for the 'wax' or polymer finish.
Wear safety glasses and remove any jewlery. Sounds silly, but make sure you keep the PC on the vehicle for starts and stops - at one point I lifted the PC to soon a got product in the face.
Go slow, I used a setting of 3 1/2, but since you'll be using an abrasive, you might want to start at about 2 or so.
Just go slow and inspect your work. You can always repeat your process, but if your too agressive, you can't go back in time.
I have to say that I'm very happy with my results. A super glass like finish unlike I've seen in a very long time. I'm now deciding how to tackle my wife's 6 year old Regal, that needs some extra work like what you're doing.
Good luck.