Both the np32 and 31 have low quallity keybeds..
So in a dual keybed Genos you want a great keyboard as lower
As thats generally where you play the piano sounds..

There is no really good 76 midi keyboards for sale..
Which makes it best to use a high quallity used keyboard,
Think G70, motif ES or others, just as a midi controller

And the combine it with a small tablet running V-console
Which gives you the number of sounds required for 2x76 keys