Just discovered a forum new to me, Baseball Fever, that has 10+ years of individual ballpark discussions. Detailed historical photos including advertising. You'll need to register to see the images.
https://www.baseball-fever.com/forum...green-diamonds
There is a 400 page thread on the forum's project to render 1923 Yankee Stadium in astronomical detail including all of the banners.
https://www.baseball-fever.com/forum...-3d-renderings