The vacuum advance would advance my timing under low/partial load situations?

Yes.

Which actually seems like the reverse of what would be true.

??? You want more advance at light loads.

So if I had a vacuum retard dizzy, I could set the static timing high and then when pushing it hard, the vacuum would cause it to retard the timing a little bit thus allowing me to take advantage of more timing under partial loads.

No.

Or what?

Low load = high vacuum. With a vac retard dizzy, low load = less advance. WOT = full advance.

I'd be looking for advanced timing when not under full load, thus allowing slightly more power and more efficient running and better gas mileage when not flooring it... Right?

Yes, that's what you want.

Dwell meter talk, I was thinking of the dwell meter being able to read RPM, not timing.

They typically only go up to 2000 rpm or so, at least the old one I had. It's for tuning at idle.

So yeah, I just use a timing light for setting the timing. Right now it's set at about 17degrees advanced at 1krpm. It's hard to set it and see where it's at when running at 3krpm because I'm trying to read little marks on the crank pulley. I could get out a permanent marker and make the marks a little easier to read and then I'd probably see what the full advance is.

Clean it with steel wool. Make area with the marks shiny.

Tunnel rams... Coolness. So, if the only benefit of the ram tube would be adding a nice radius, then what's the point of getting a full air horn vs just a little stub that is radiused? Nothing?

Remember that intake isn't a steady stream of air -- the air needs to be accelerated every time an intake valve opens. There are also all sorts of shockwaves going on that raise and lower pressure in the ports, sometimes even right out the carbs.

Long horns add mass to the air column. It's harder to accelerate, but tends to stay in motion better. That may be beneficial, or it may be detrimental. Depends on your carbs, manifold, ports, cam, header, exhaust, how you drive, etc. etc. etc.

Good for some applications, bad for others, no effect on some. BTW, you can't really even get stub horns into the Volvo airbox (even with a remote filter) without them being too close to the lid.