Oh, I didn't realize he was the only pitcher in league history to pitch all of his games at home
True, but it still would invalidate your points to some extent. McLain would have pitched, what, roughly half his games at home? And if anything, the park shrunk some as they expanded the park after Frank Navin died back in 1935 because that's when they started adding to the upper deck and created the upper deck overhangs the stadium was famous for.