Yes, Organ Stop Pizza is a cool place. Haven't been there myself but know of several who have and werer duly impressed. I remember reading about it on the Piporg-L, the older pipe organ discussion board hosted by Univ of Iowa. Charlie Balogh gave lots of updates as construction progresses on the building, organ, and custom console. They left space in the front for a set of un-mitered, 32' Diaphones which they acquired about a year after the grand opening.
The other theatre organ Mecca (not in an historic theatre) is the Palace de Musique, of the Sanfilippo residence in a Chicago suburb. Search for "Sanflippo Wurlitzer" on Youtube. I have been there on 3 occasions. The installation is over-the-top: polished hardwood floors and track lightning in all 6(?) chambers; furniture finished resonators on the exposed 32' Contre Bomarde and 32 Hope-Jones Diaphone; screws used on the Wurlitzer chests, bearers, offset racks, etc. are authentic Wurliizer screws all pointing in the same direction! I can go on and on but you get the picture.
I have the Paramount 320 and it loads about as fast as the 310 on my SSD. The Paramount sets are too dry for liking but fortunately the MOTU interfaces offer EQ along with some basic reverb. This feature was designed for home studio recording when vocalists would like to hear a some reverb on their voice in the mix or headphones. Works great for Hauptwerk to help moist up some dry sets as its available in all channels! I have mine set just enough to give you a little ambience. Most guest organist don't know its even there however if you turn off you know its missing.
With theatre organ playing, there is a lot of hand registration that can take place. Allocating some spare pistons to a cymbal crash or tuned percussion is the norm for VTPO as its easier to quickly press a physical button than aim for it on a touch screen. On the POW organ graphic, you see two drawers of buttons under the keydesk. On a real Wurlitzer, these pivot out on single shaft and provide all the sound effects for silent movies. With modern computer relays, more buttons have been added for more functionality like memory levels, etc. For my rig I have added a Launchpad mini under the keydesk in a custom drawer using telescoping 6" rails. With theatre organs there is always the need for extra stops tabs and buttons.
Danny B.