With today's tires and our 85+year wheels, I have found:
After 40 years with the dot in the valve-stem alignment, the tire show 1/8" wear.
After 40 years with the dot opposite the valve-stem, the tire shows 1/8" wear.
With the dot on the outside: 1/8" wear.
With the dot on the inside: 1/8" wear.
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Ignoring the initial reasoning for the placement of the tire's dot, today's alignment is truly aesthetic and a nod to historical accuracy. Ignoring it's practical irrelevance, I like to strive toward visual historic accuracy, and follow the guide as recommended by tire booklets of the 1920s and '30's, and use the dot as a 'balancing' mark.