Steve,
The measurement off existing would work (assuming they are correct). I have a template I could email you for this purpose from a factory mirror option that will get you on the mark. I would print and mail you a copy but I am leaving the U.S. for a month today. The other option is to get inside and drill out using a small pilot bit, carefully of course.
https://www.flickr.com/photos/advance-design_parts_co/8416411203/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/9647482921/in/album-72157631868452754/