Hi, Mouse:
I don't have nearly the prolonged-rain experience you do, but I've had some here in the Ohio River valley. I second everything you said, especially about having a tent that you can pitch fly-first. I also carry my tent fly in a separate stuff sack from my tent body. That way, when I have a reasonably dry inner tent, I don't have the wet fly in there with it, ensuring that the inner will also be wet. I don't know how long you'll really be able to keep the inner dry in prolonged rain, but in the two-day bouts we sometimes have, it really helps.

Another advantage of a fly-first pitch is that you can use it, without the inner, to create a reasonably dry spot to eat lunch.

One thing I wonder: if walking in prolonged rain, would a two person tent offer any advantages over a one-person tent? For example, would having extra room to store gear inside the tent instead of in a muddy vestibule be an advantage? Or would it simply give you enough room that you aren't jostling the rain fly when you move around, causing condensation or other drips into the tent? Around here, I've never had any problems using a one-person Hubba - but again, about two days and nights is the worst I'm ever exposed to.