The cut outs are factory to give access to the wipers, I have been looking at the ford transit rear door wiper motors they look like a good fit with a 90 degree sweep need to research that a bit more

1940 Chevrolet 3/4-Ton
"Project XJ-PU-V12"
In the Stovebolt Gallery
More pix on Flickr

In business, words are words, explanations are explanations, promises are promises, but only performance is the true reality.