I was planning on taking some before and after pics of the mounting holes. 95% of the projector is outside of the fog light housing, but most of that is covered by the mounting bracket.
Here is a pic of the projector mounted from the back side. You can see most of the reflector bowl is outside of the housing which is why I painted them with high temp caliper paint. The locking nut you see on the threads can be removed as it is not needed with this application.
Mounting bracket installed.
Starting point of the 880 bulb locking tabs. Its big enough to slip in the sanding drum on a Dremel. Back and front side.
Back and front side of fog after dremeling. Still had some more cleanup.
Also, had to open up the mounting bracket quite a bit on the back and top so it would swivel properly.
I had to relocate the hole for the screw and spring on the driver's side fog to the left of the OE hole because it was hitting the reflector bowl due to the angle in the OE location. Passenger side OE mounting location was not an issue. You can see there is only an inch or so that sticks out past the mounting bracket.
As Aarkon suggested, I used two 4mm stainless steel bolts, nuts, and washers to secure the projector to the housing. I used the mounting holes for the shroud on the projector to secure them to the housing. I had to drill out the shroud mounting hole with a 5/32" drill bit to fit a 4mm bolt. You can see the head of the bolt on each side of the lens.
Here is a mockup pic with the micro gatling 2.0 shrouds, but think I am going to use the 1.0 shrouds.
Below are the very hard to find 1.0 shrouds that are no longer made, but look better than the 2.0s IMO. The 1.0s are like a press fit versus the 2.0s where they are mounted with screws.
To be able to fit the 2.0 shrouds, there is an inner lip on the inside of the shroud that needs to be ground down flush so that it slips over the lens mounting bracket. You have to do this so that you have enough clearance to put the fog light lens cover on.
Aarkon, if you have additional information or pics, feel free to add them as I might have forgot something.