The dot is the light side of the tire. It is to be placed at the valve stem.
I have a Snap-On computerized balancer at my disposal. I have Dynabeads in the tires.
We had a customer buy a set of wheels that were way out of balance to the point they needed 3 1/2 ounces of lead weights. He couildn't bear that ugly stuff on his shiny new wheels. So we got him some Dynabeads and installed them. Worked very well on a very shitty set of wheels. I was sold. And I was quite skeptical prior to that experience but that's changed.