Hello Kristian,
It is doable, but unfortunately there is no NRPN for the buttons on the 01v96, except “on/off”. Maybe you can achieve something through the “Cascade Link” function, but I think not. The 01v96 uses desk specific SysEx messages for “select” and you will need some way of sending them from a separate controller or from one desk to the other. When the desk produces these messages they do not appear at the Midi-Out connector, only on the USB to a computer for use by Studio Manager, even though they can be received and understood at the Midi-In connector. Please have a look at this PDF which gives a few clues about effective garbage in garbage out using the Yamaha digital desks.
The message you want to be able to send - select (for ch17) is F0 43 10 3E 0D 04 09 18 00 00 00 00 10 F7 (and for ch18 the end is:) 11 F7 …etc.)
I am probably going to update this page a few times. If you set the Studio Manager connection in DIO setup to use the Midi connectors (instead of USB) then I think that the desk will send and receive only SysEx on the Midi connectors, and for every parameter. Do the same for the second desk and connect their Midi-In’s to their Midi-Out’s and they should then talk exclusively Sysex and each one should follow the other in every respect. They would need to have the same ID number. It works between a desk and Studio Manager, so I think it must work between 2 desks! You would need to make sure that they hold the same data before you start work by doing a bulk dump from one to the other.
I suggest that you try before you buy!
David Kent.