By the way, the Acusticaudio guys are really active on forums and communities, so if you tell them about this thread, I think they'll chip in with useful info for all of us. If we can inform them of what we're trying to achieve here, I think we might get some useful feedback... and in particular YOU might get some useful feedback on how to sample the cab most adequately, Marcus.
On another note, did they describe the concrete differences between Nat 2 and 3 to you? Does NAT 2 only do a snapshot with the current poweramp settings, whereas NAT 3 can sample all positions of your poweramp settings and then let the user alter them on their end? That was my impression from the e-mail you got back.