I use songbook+ and have some virtual buttons annotated on each sheet music to invoke things like variation changes and sts changes it all works.
What I am struggling with a bit, is the midi bass pedals on the organ: I need toggle ‘globally’ ie set to either on or off for the bass pedal style voice, and override ideally the same voice so that it sounds according to pressing the organ’s bass pedals. I can of course easily mute the style’s bass track and even allocate the operation to an assignable switch, but ihavent found a way to lock the bass track to either mute or play (ideally both would be handy as I like to play from the organ and also to use the bass style if playing the keyboard in the conventional way without the organ).
Yamaha tyros etc seem to have this sorted and there are relatively ready made preset configurations like registiks and the sound elite series for setting up bass pedals and dual manuals, so wonder if there is any similarly defined procedure for setting up midi bass pedals on Korg PA900, there is nothing obvious in the user guide
At moment looks like some style editing might be required to accomplish this which may be a bit too tedious as I have 100s of digitised sheet music so a simple override or something would be best.
Ps love the ease of integration of PA900 with the iPad ongbook+ app so much less faffing about than with tyros, apparently the new flag ship
Yammie genos has even better integration but is expensive.