Ok, might be a bit hard to see from this photo, but here's what I've done.
I use bar-backs to both raise and move my handlebars up and back. Because of this (and I prefer the look), I've taken the handle bar cover off which gives me lots of mounting options.
I run two GPS units when I lead club rides (different info on each) but my main Garmin Zumo 390LM is mounted with a RAM mount ball clamped directly at the center of the bars, between the bar clamps.
Now from this angle you can't see it, but the flat top of the GPS shade is exactly in line with the bottom edge of the instrument cluster from my eyes viewpoint. So none of the instruments are obscured, and I have a great view of the GPS. IMHO, you don't want the GPS too low because you want to be able to see it with your peripheral vision or with a very short downward glance. Eyes on road as much as possible, so the less distance you have to glance down the better. That's why I HATE GPS in the top of a tunnel bag.
And for those wondering about all the RAM mounts, well I also use them to mount cameras, TPMS on long trips, and other junk.
Oh, and this as an early test ride of the mounts so the wiring is just outside and down thru the glovebox door. Once I decided on the permanent location I ran all wiring down thru the hole beside the steering tree. All wiring neat and out of sight. Oh, and I also use a RAM locking knob on the GPS holder for the Zumo so it can't be unscrewed without the key.
So that's my solution. Dump the bar covers and get creative with RAM mounts.