Yup. Set initial and centrifugal to what you need. Then set the vacuum can. Best way I've done it is to tape a vacuum gage to the windshield so you can see where things are while driving. Then tune the can to provide max advance without causing a surge or misfire. Race engines in race cars don't benefit from a functioning vacuum advance. Pretty much any engine that experiences widely varying throttle levels will benefit from a properly tuned one. Gas mileage and throttle response are where you see it. I've had cars I drive daily with 4" of vacuum at idle that ran great with the vacuum advance functioning. But - at some point, you get out of the adjustability range of the cans. At that point you're probably in a race engine/race car situation anyway.
Edit - Thanks MAgoo - I'm not up on the Pertronix stuff. I'd still argue that their instructions are not 100* right though assuming they adjust like others'. You're still adjusting the vacuum level required to move the arm. Not the number of degrees. Once the vacuum climbs high enough you will get 14* added no matter what you adjust.
