PeteF.- Heh heh, I wouldn't be in too much of a hurry to use up that Griot's wash, it's my favorite shampoo
You'll need some pretty aggressive stuff to correct an Audi with the PC, and it'll take a while. If you have access to a rotary I'd sure use that for the major correction. Can't really comment on the SSR line as I haven't used it but the Spies-Hecker clear is quite hard and it's nice and thick (so you can really work it if you need to).
Treat the black plastic "B" pillar (and the similar trim by the trailing edge of the rear doors) like sorta-soft paint.
I think you'll spend enough time on the marring that you won't be all *that* inclined to do multiple LSPs

I'd choose between the
Souveran and the Natty's and just use one of them over the EX. If you *do* want to use both, I always use Souveran as the last step since it doesn't last all that long compared to other LSPs.