On my Gemini I've changed it to 550 to get the most out of the screen real estate without getting things changed around too much. If I go higher Agenda (and do believe I got trouble with some other programs as well) will be more ore less useless, and I seem to remember that if you go above 600 the "software-buttons" on the right side of the screen will move to the bottom (at least on Android 8, as it is on the Gemini).