Is anybody familiar with "gluing" on patch panels?

1.) I'm wondering how far inside the outline do I mark for cutting? (photo 3)

The width of your flange tool. Usually about 3/8"

2.) Do you flange the body, and overlap the patch; or flange the patch and slip it behind the body for bonding ? (when we're to that point of prep)

I flanged my body, then patch on top.

3.) What is the best adhesive to use?

Sorry no info on adhesive, I prefer to make ALOT of small spot welds, keeps heat down, no warpage that way.

Just my .02 , hope it helps, Eric