If your vacuum advance is hooked to ported vacuum you want have vac advance at idle. I personally like the stronger idle quality from vac advance @ idle. For emissions purposes it was hooked to ported vacuum.
Forget about your timing light for a minute and just try setting your timing with the vacuum advance connected to full vacuum and advance it til it pings. Retard it until it doesn't and record your total timing advance and base timing with your timing light. Using this method usually gives you the best results believe it or not and then knowing your settings gives you a good base line to dial in your advance curve and to further fine tune your timing. With Vacuum adv at idle your idle speed will be higher so you will need to adjust it accordingly. But don't be afraid to play around with it. You'll be glad you did because the results will be quite noticeable. Just keep in mind, it should start easy hot, and absolutely no pinging.
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