You could always use an external keyboard with a split function MIDI’d into the Crumar, just set the same MIDI channel on lower and upper. A 76 gives you a good three octave overlap, which is a healthy range for a solo sound (an 88 even more!).

There’s a demo of me playing The Beatles’ Blackbird over on the Roland sub-forum using the technique with guitar sounds.

There’s airways a drummer playing in my mind, and playing rhythmically well enough to lock with him has always been the secret to good non-classical music. To that end, the two handed rhythmical style has always been my goal, and one of my chief criticisms of the arranger paradigm, which Balkanizes your hands pretty severely. We are bisymmetrical creatures, and using both sides together always seems to lead to strong results!

To be honest, the split technique isn’t anything totally new. You would be expected in a lot of piano music to do this, only you’d have to do it with your hands overlapping (think Debussy or Bill Evans). All the split trick does is allow you to play those close overlapping figures with your hands comfortably apart and not tripping over each other! It’s nowhere near as ‘outside’ a technique as Zawinul’s reverse keyboard layout, but with the same goal in mind…

Get yourself out of rote licks and all too familiar lines and licks. And, once discovered, there’s nothing to stop you from attempting to play it in the close hands position on an unsplit layout. It’s just harder that way! 😂🎹😎