I took one of these Ram flat mounts and a large neoprene washer, and drilled my windshield for 2 sews with lock nuts. Then I can just attach any RAM mount when needed. I mainly use a handlebar mount for my phone, less vibes, but when I want to run both phone and GPS its good to have the option.
I stole the basic idea from someone here on the forum, but can't find the thread now.
Its a good mount position for a GPS it is almost Heads Up Display level. Puts my phone or GPS right above the tachometer.