So you would consider the two ideal water sources for IPA to be Bull Run and Burton know that Burton is roughly the opposite of Bull Run in every way? It seems like if those both work well, so does everything in between (all water).
Another problem with pH strips is that they have poor resolution and there is user error. Even if you identify and correct for a bias, I consider the narrow range ones to be not accurate enough for measuring mash pH.
When I used them I found myself trying them under different light sources and basically trying to justify what I thought the pH would be based on spreadsheets. This is dangerous, but it is human nature and we'll all do it. When I figured out what I was doing I bought a pH meter. I now think about water much less and my beer is better.