OK. I'm interested in verifying this measurement as much as possible.
So I just pulled up some old photos online from Steer Stadium in Oak Cliff, across the Trinity River from Dallas (later Burnett Field).
These aerial photos were taken that very same year, in 1930 and are similar to Google satellite view today.
Pulled my tape measure out haha - I'm sure there are more precise ways to measure this on the computer, but here you go.
Photo #1 -
The LF line was 329 at this stadium, so for reference 329 feet = 1.625 inches (see white arrow) - The top of the levee is very visible beyond LF as there is a white line/path on top (right at the 2 5/8 inch mark on the measuring tape)
So 1 inch = 202.46 feet.
Photo #2-
2.625 inches = 531.45 feet (see white arrow - the 532 foot measurement as described seems very plausible, given the description).
This would place the ball well up onto the levee beyond the stands as described. Willingham was a right-handed batter and the outfield stands do not extend past left-center field, according to these photos.
So the ball must have been hit to straight away left or slightly toward left-center.
Photo #3 - This was taken in 1932 - showing the stadium, levee and river.
I put a white x on there as a possible landing spot up on the levee.
Ok. I'm done. Admittedly I got WAY too into this
