31 Aprons rear holes

[JohnB15632]

My aprons do not have not have the holes in the rear that match up to the holes in the front of the rear fenders.

So many people tell me that holes such as these should be done before I prime paint the aprons.

Therefore, does anyone know about these holes? Does anyone have the dimensions of these holes that I can add to my aprons?

The attached picture was sent to me by a fellow restorer.

Thanks,