This is usualy a semantic discussion whe ever it comes up. The best answer includes all the ignition advance information or else somebody will get confused every time.
If you include initial advance plus all the centrifugal plus all the vacuum advance it should usualy add up to around 52 degrees for our old school wedge head SBC's.
This would be at a high rpm cruise situation. Like driving down the highway and not under any additional load.
More advance than that is typicaly too much, and less than that may leave efficency (power) on the table.
If you want to address wide open throttle ignition advance, you do not count the vacuum advance in that calculation. Vacuum advance does not function with your foot to the floor so it does not add anything to the equation. The rule of thumb for that sum of initial plus all the centrifugal is about 36 degrees. That is the number to shoot for.
This "36 degrees" is the field you play in when you are trying to pin down the curve for high preformance, improve the idle, and have a good transition from idle to part throttle . The 2 components of this "36 degrees" are initial setting plus all of the available centrifugal advance. If your car likes it when you give it a higher initial setting, then you can increase the inital setting BUT you would want to decrese the available centrfugal advance available in the distributor centrifugal advance menchaniaism. The goal is to keep the sum of your initial plus all the available centrifugal advance equal to about 36 degrees. One goes up, the other needs to come down. You either hurt power or hurt the engine with more or less than 36.
If you follow the math you will see that the vacuum advance mechanisim is probably best if it provides about 16 degrees of advance at cruise. It just ends up that way. 36 + 16 = 52
Typicaly you may find your car likes maybe 12 degrees initial advance and a centrifugal with about 24 degrees available in it. That works as a baseline for a performance ignition curve for many applications. You may need less initial and more centrifugal but the sum should remain close to 36. Bigger cams may enjoy even more initial advance. You would have to play with it to get it perfect.
Hope this helps somebody.