All you need is a decent eyball with a solid connection to a properly functioning human brain in a semi lighted work area. LOL I hang a plug from the wire and slowly roll the motor by hand untill the plug sparks. Pick one and get it very close to the fire mark. Then get the other set to spark at exactly the same time. As long as gap is close, you are getting close to a blast around the block. When they are perfecly sync'ed, swing the plate to make them fire on time. I have set them like this for years and @ 10krpm they seemd to be fine. I got a light and all was perfect so I haven't pulled it out of the box since. If the advancer unit feels free then all is probably proper. (so far) A touch late on the time seems to work better than advancing it more than stock but make them them EXACTLY same and it will pay off.
