I was feeling somewhat too limited by the Hammond Organ-style registration preset keys and the Banks matrix keys. Yes there can be a lot of presets as it stands, but - call me insatiable - I wanted even more leeway.
So I fixed that - in Logic with VEP7.
At any moment while playing, I'm now able to select any one of 16 complete Great Rieger Organs, each having its own registration presets and responding on its normal keyswitches accordingly, and each can respond to all 5 MIDI channels appropriately. To do this I built a simple MIDI-controlled instrument-chooser in Logic's Environment.
I suppose I could have put all 16 organs in Logic, but for convenience I've popped them into one VEP7 instance and used 16 cloned AU3 VEP client plugins in Logic - all clones connected to the one VEP instance, each routing to a different VEP port.
The "organ chooser" I built in the Environment is dead simple. Note Ons from multiple MIDI keyboards on any channel are routed via a MIDI-controlled Cable Switcher to one of the 16 VEP client plugin clones, one clone for each organ on its own VEP port. And as old hands with the Environment will know, the important trick with cable-switching MIDI notes is to prevent hanging notes; so I've used the old method of sending all Note Offs to all instruments all the time. Job done. Also, any incoming MIDI CCs on any channel are routed along with Note ons to the one organ selected by the Cable Switcher.
A pic of my simple organ-chooser mechanism in the Environment is attached below. A Transformer is used to split Note-Offs from Note Ons, using the "Condition splitter (true -> top cable)" Mode, the Condition being Status = Note, and Velocity = 0. Each of the 16 output Monitors is cabled to one of the 16 Instrument Strip clones that have one AU3 VEP plugin inserted for all 16 clones; each clone is set to All MIDI channels and its own port number.
My old but still not too shabby 4.2 GHz 7700K CPU is coping at around 45% usage. I guess I could knock that usage down a bit by not using the factory-loaded audio fx plugins in every individual organ. [Edit: it's around 23% straight after launch but then some while later after some varied use, for some unknown reason it roughly doubles CPU usage suddenly and stays there].
The number of preset registrations I can set up and use with great ease now is just bonkers and I'm loving it!