Vacuum advance information and myths

All the VA does is supply timing. The engine doesn't care how it gets the necessary timing to run as efficiently as possible.....as long as it gets it.
If the engine has a dist that has the timing locked, ie it idles at 36*, has 36* at WOT & everywhere in between, then it is unlikely to benefit much, if at all, from VA.
Once the engine is at cruising speed, MVA & PVA are equal in what they do. The benefit that MVA [ has over PVA ] is that MVA is active at idle & PVA is NOT. Depending on initial timing, MVA can substantially improve idle quality, vacuum & tip response; the engine also runs cooler. Rarely is MVA not a benefit.