Nice work. How about a comparison of the truly "elite star"cards versus the rest of the star cards? Lets say Cobb, Young, Johnson, and Mathewson vs the rest of the "star" cards. My guess here is that the elite "star" cards would favor PSA and that collectors would be more willing to chose between PSA and SGC with the other star cards. It could also account for a different type of collector. The T206 collector vs the collector who wants lets say a Cobb card for their collection. I think it would be interesting to see how the numbers align with perceptions.
Thanks again for all the work and an interesting thread.