Would it worthwhile to screw in as much timing it takes to make it detonate, then pull it back some? Seems like a light becomes pretty useless if the ignition is retarding on it's own at RPM.
Old Post, but That's how we did it back in the day. Dial it Up, then drop er a Lil, run her, listen well, then check for kickback at starter. If no Det, good to go!