Joe, re: Pelz's test, he explains that he filled a small bucket with water and epsom salts, enough to make the ball float. Then he spun the ball in the water, and when it came to rest, he put a small dot on the side that finished up. He then spun the ball again, and if the same spot ended up facing up, it was clearly an unbalanced ball (though likely only the barest fraction off center, creating a heavy and a light side). If a different spot ended up facing up, then it was a perfectly balanced ball.
Today you can eactually buy a little machine that spins the ball for you, I don't even think they're that expensive.
He recommended saving the perfectly balanced balls for special occasions, and lining up the off balance ball in the manner MM initially stated, so that it would roll end over end, rather than being pulled off center.
I actually performed this test on one dozen of the early Strata balls. I came up with 3 or 4 perfectly balanced balls, the rest a little off. I never noticed anything regarding the performance of the balls in play, but I'm not exactly Iron Byron in the consistency arena.
I believe he has stated that today's balls test out MUCH better than the older balls for being perfectly balanced. Makes sense if you think about the imperfections of wound balls versus today's manufacturing processes. Wilson did introduce a ball a few years ago that was supposed to be the truest rolling ball (can't remember the details, I think Crenshaw was the most visible endorser, but it didn't last in the market).