Hey Guys - need a little help please !

I had the headliner replaced on my 68 Dart Gt and the upholstery shop didn't cut the hole out for the dome light. I can feel the wire but don't know if that is exactly where to cut the headliner to fish out the wire & see where the holes are in the center brace to screw the dome light housing in.

Can someone who has a 68 dart with a center dome light measure the width & length of the center roof brace and also from the windshield to dome light so that way I can cut the headliner in the right place so I can attach my dome light please !!!

Thank you very much guys !

Mike