I recently obtained the correct wiper motor for my 1931 Deluxe Roadster. The car came w/o a motor and I am not sure exactly where to locate it on the windshield frame. Is it just where it clears the best? Is there an exact measurement where it should be mounted? There are two (2) snap buttons located on the driver's side frame about 2" apart. They are in the area where the wiper motor would be mounted. I am not sure what they are for.