So you feel splitfire is a good plug??
I have used splitfire and it was not eventful but really the question about the traveling of the spark seems a little way out there for the average guy. The next problem is to produce a proper scientific study of a products merit. This would be even further out there considering all the factors.
To give a "simple" answer based entirely on a guess and assuming all your information is correct I would say the spark probably uses both maybe even alternately depending on many different variables.
So wrong it does not favor one pole entirely.
Once again not pure science but the "longer" pole closer by a fraction I assume would wear down then they would be even then they would wear evenly. Or maybe not. Just a guess.
I think splitfire would have your answer.