My advice, take it for what it's worth...
The PC isn't the most powerful tool, but it will correct BMW paint. I have corrected Bugatti Veyron paint with it, which is WAY WAY WAY WAY WAY harder (the Veyron makes Audi paint seem even soft).
Since you are new to polishing, I would focus on your technique:
Work a 2 x 2 square (you have this down pat), work slow arm speeds (count in your head 1 second per inch) and use firm pressure. The pad should spin, but slowly.
Common mistakes begineers make on hard clear coat:
- Moving the polisher way too fast
- Not near enough pressure
- Not working the product long enough
- Working too big of a square
The PC and other ROB designs such as the Griot's and Meg's G110v2 are pretty capable...
Now for pad size, if you can, go with the 5.5 inch pads. They are more efficient on a ROB (random orbital) machine. Thin is in- thinner pads are more efficient as well.
For your protection: If a paint sealant is doing its job, it is almost pointless to apply a glaze on top of it. Glazes are oil based products that will penetrate microscopic imperfections and lay on top of the paint sealant. Wolfgang 3.0 uses extremely small polymers that are going to create a very level surface. The lay will have nothing to penetrate and you will end up wiping most of it off as you buff it off. Whatever you don't wipe off will be emulsified into the wax as you apply the wax, then buffed off when you remove the wax.
I understand that some companies recommend this sandwich style of application, and perhaps their products are designed for this. I have not used them so I cannot give any first had account, but applying any glaze on top of Wolfgang 3.0 is really a wasted step because 3.0 is so effective at it's job of sealing the paint.
Hope this helps.