How to adjust map size on MFD using keyboard key or joystic button?

When you assign keybindings in FSUIPC7 you get the option to make the binding aircraft specific or all aircraft. So to set up a specific aircraft I go through the search function to see what event is operating when I throw a switch in the VC. I then assign this to a switch on my home cockpit and tick “Aircraft specific” in FSUIPC7 on the assignments page. Hope this answers your question. No, I am not familiar with AA0s.