Remote radar detector installation location?

Hoping there is a fellow Trailblazer owner here that can help.
I am trying to find a spot for the receiver of the Whistler Pro 3600 radar detector in an '04 Trailblazer. The thing is about 5 1/2 inches long as it is pointing forward & it will not fit where my old one did, behind the grill. I located a spot just to the side of the license plate, but don't know how to mount the bracket. The screws need to go through the bumper cover at the top of this opening, so I can't remove the cover to get to the area above. There is not enough height in the opening for a screwdriver. Wonder if I can get to the bottom of the cutout & mount the bracket there? It's raining out, so have to check later. If anyone has any experience with this, let me know your thoughts.
Thanks,
kev
Edit: Added image. The yellow box is where the mounting is the issue. The location of the orange box would be easier, but I would have to cut a bit of the grill out. The more I look at it, the more I like the orange box. Not too low & still near the license plate & I can probably mount it without a hassle. What do you think? Attachment 6656

While I can see your predicament, the higher, the better as far as range goes.

Go with the red block area for best performance.