Manifold or Ported vacuum source???

[70GMC396]

What source do most of you run for your vacuum advance on for Late 60s - early 70s big blocks engines? I have heard both ways - old school saying manifold vacuum on the bottom of the carb and others ported only, doesn't seem to be a lot of opinions in between. Can there be a right or wrong answer here? I have read dozens of threads on the subject but what SHOULD we be running on stock carb/engine setups since we usually had TCS controlling that for us and now TCS is usually non-functional? Is ported more reasonable for a smoother, longer application of advance? Seems like the old muscle car theory of carb manifold was just to smooth out idle/heat during the lower rpms for the streetability and not worrying about vacuum disappearing after that since it wasn't important on a performance set up?
Thx