"I don't see why using NRPN's would limit you"
It's due to my complex setup of the pots and switches and the limitation of the MIDI CPU that translates their values into MIDI messages.
The CPU has a set boundry/syntax of commands.
What I was hoping to do was make a pair of pots synch'd to change the parameters they alter by pressing a momentary switch. A multimode effect.
So say.. Pot1&2 in first mode will change VCF cutoff & Resonance, then press a switch and they change to alter LFO1 freq & Depth.. press the switch again and they become LFO2 Freq/Depth.. press again and they become something else and so on..
The command structure appears to only let you do this if they are standard CC#'s. Because NRPN requires at least two CC's, it's that additional msg that must be sent that takes the ability to multi mode a set of controls.
I also wanted to do the multimode feature for a pair of "hat" switches.. they are like old time Nintendo "+" controllers.. UP/DOWN/LEFT/RIGHT switches. So they could be used for say SLFO3 Freq. UP/DOWN and it's Depth UP/DOWN... hit a separate switch and it would change to SLFO4 controls.
The FIRMWARE manual is here is you ever get curious:
http://highlyliquid.com/support/docs/pdf/MIDI-CPU-Firmware-Ver-1-2.pdf3.1.1 is where the CPU's Sysex format can be found.. right below it is the "layer" configuration explanation.. and then 3.2 talks about all the logic modes.