Won't most drop the right out anyway ? I'm just thinking in terms of what has been mentioned above (PA28) on the key OFF - LEFT - RIGHT - BOTH - START ??
Well sort of except some use toggle switches (Agwagon, Twin Comanche etc.) and some don't have the "start" position (starter is activated by a separate device)
Toggle switches were always fun. Pilots on a runup would turn one mag switch to off, get a rough running engine and return complaining that the mag on that switch was bad. They were always puzzled when I would go to work on the other mag and fix the problem. Think about it!