How much total advance?

If it starts ok at 22* initial, crank it up to 24* and see if it pings under load. You really would like to generally get the most advance that you can without having detonation issues.

Put a light on it and see where the total is and turn it up a couple degrees and drive it. One thing to remember, when you here it ping may not be where it's starting to ping. I always pull an extra degree or two out as a safety margin incase you get a bad batch of gas etc.

The reset the mechanical so you hit that total number using your 22* initial.

If you can dial in the vacuum advance, it will likely help with fuel mileage. It's just another area that takes some work to get right.