Microtonal "playing" with note performer

I’m trying to create a way to play microtonal intervals with note performer being the playback template in Dorico. The playback works fine, but I would like to have a button that would lower the pitch by 50 cent when playing with the keyboard.

Does anyone have any idea of how this could be achieved? I almost managed to do it with pitch bend -command from my Fader Master Pro -controller. But I can’t get it to exactly 50 cents, it’s either too much or too little… Any ideas would be appreciated!