Can't it be either or or? Creating a Floating Division for the desired sample set you could assign Pianoteq as the top or bottom manual on the fly. As a musician, it would feel more natural for the piano to be the bottom manual, especially when using both hands vs having to reach up to the 4th manual. If you review this video of Pierre Fracalanza you'll see what I mean:
https://www.youtube.com/watch?v=sdQbgdeVArY
Speaking of the Armley-Schultze, I've incorporated it on my 3 manual console by assigning the Swell and Echo as Floating Divisions. Three different routes are assigned to spare pistons:
The top manual is just Swell,
The top manual is just Echo,
The top manual is combined Echo & Swell
Danny B.