Good idea

Personally...I hate the metal straps because it makes the window look unfinished. Just my opinion but I would figure out a latch system from the inside. They make various latch setups for manual sunroofs that clamp down to make a seal but allow you to remove the window completely for the doggie.

Or could you add more bolts at the metal strap area to insure the seal?

Still I love the function and your dog seems happy.