What I did is create an enumeration with the numbers you need to put in R1 to select the property of the pokemon you want to get or set. When you have
mov R0, blabla
mov R1, #45
mov R2, fubar
bl set_pokemon_data
You can right click #45 and choose the correct property from one of the submenus.
Use Ctrl+Z (or was it alt+q?) to force zero offsets [R1, 0] to be interpreted as structure [R01, #npc_state.field1]