[DanEC]

I don't believe I've ever heard of setting initial timing by shooting for the highest vacuum gage reading. I use it to set the idle mixture setting on the carb - but not timing. A lot of timing at idle will smooth an engine out and make it sound happy but as soon as you start driving it and mechanical advance starts coming in - it will get unhappy real quick. I know a lot of old timers set timing by ear - I'm sure not that good - but a timing light is a much better solution.