I received a response from Jeff Brouws, so I can now complete my project:
No problem at all in terms of contacting me...we're all brothers here.
I can't say why we made the determination we diid, but we went with the building that was at 3500 North Broadway. I felt that the buildings in the background to the right could have been the same ones in Ruscha's photo, but modified since Ruscha's took the picture.
Not certain however. Hope this helps. It's a burrito / taco stand now. We ate there..it was great.
I realized after the fact that MM had done a "best guess" in certaini towns and that was fine.
I believe I did locate Rimmy Jimmy's in AZ...there was a definite foundation there and the owner of the present gas station there had a picture of the former Rimmy Jimmy's hanging on the wall and knew where the original location had been.
Exit 233, to the slight SE behind the gas station.
And here is the assumed site of Bob's Service - a little in contradiction from what Möll stated in his e-mail, but it is the place he photographed back in 2009.
Bob's Service, Los Angeles, California [Sep 2014]