Join Date: May 2005
Location: Mayenne France
My Motorhome: Frankia T640 FF2
Thanked 208 Times in 185 Posts
The lines you drew on your original pictures were misleading, it looked as though you were anticipating removing more than what is shown in your last picture (the one with the rubber strip fitted one).
If you are only going to cut out the recessed aperture I'd say that will be just fine.
I'd suggest that a bonded on glass will more than replace any stability lost by cutting out the metal.