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http://bimmer.roadfly.org/bmw/forums/detailing/forum.php?postid=1430487&page=1
Do one section at a time and wipe off the product residue. I do one section of the hood at a time, wipe the residue off, finish with the hood and then pull it out into the direct sunlight and examine my work and the results before going further. Know what you've accomplished before doing the whole car with the routine and approach you are using.
I'm just learning myself, but last weekend I used the yellow pad and SSR1 on my truck. The weather was such that I couldn't verify my work (too overcast), so I did the whole truck like that. Turns out I really should have used SSR2 with the yellow pad. The truck was greatly improved but not as good as I wanted.
As for following up with PwC, then EX with a finishing pad, I think the finishing pad with EX is fine, but I'm not sure about the PwC. I would think that would be fine though since you've already done swirl removal. As for topping PwC with EX, I'm not sure about that. And you're paint is going to be pretty clean after the SSR2 I should think.
Yesterday I did the wife's car with the yellow pad and SSR2, well, I got most of it done. I then followed up with AIO by hand and then topped with UPP and finally Trade Secret. I really only used the AIO to be certain I got any SSR2 residue removed and as a good base for the UPP.
Certainly others can and will offer advice and correct me if I've made a statement in error here.
Hope this is of some help.