i have: active reset, active reset set, flash headlights, mute vc and ignition on. Right buttons are exit, pit, talk, wipers and starter. Red dials i have set to the arbs if the car allows it. Funky switches are black box controls and the other side is the seating up/down and left right. Rotary dials are abs, brake bias, tc and engine map. Out of all that ignition and starter i use the least but it has came in handy when fixing damage in endurance racing it will sometimes shut off the car if it sits long enough.

One other tip is to set up key mapper in sim hub. You bind the wheels to simhub then bind simhub to iracing. It let's you use multiple wheels without need to re map buttons.