I too had (still have) a RamBone for the GPS anchor. Used it for a long time on my 1st Gen with the longest (5" I think) Ram Arm and it was perfection.
But on my 3rd Gen, once I installed a HeliBar Bridge Riser the RamBone, she don't a fit no mo'.
Ordered and installed a threaded Ram ball into the provided hole in the bridge and that is generally where I mount the GPS from with one of the mid-sized (3" I think?) Ram Arms. But it is not ideal.
In my opinion, that location is a bit too low, as it makes you look down too far, and opens you up to all kinds of unhealthy crashing carnage by taking your eyes too far off the road. But, unlike on my old 1st Gen, the longer Ram arm on the 3rd Gen causes the GPS to block the instruments.
I also have a threaded ball in the left side mirror mount hole, and I have experimented with mounting the zumo up on the left handle bar. It is a better place, re: keeping some peripheral vision forward on the road, but it is sort of clumsy in some other way. You have to be careful how you position it or it will foul the windshield at full handlebar turn (in parking lots etc.) and the afore mentioned vibration can be a problem on a longer than the shortest arm length.
For me, the gold standard is how I have my GPS mount (same GPS, extra mount) on my old 2004 Suzuki ManStrom. I have the "Strombone" mount on that which puts the GPS up centered behind the non-electric windshield, but well above the instruments. It meant running some custom audio and power cablkes through the inside of the faring to prevent having lots of dangling cables in front of the instruments, but that seems a small and easily surmountable concession. (photo was taken before I routed those custom cables)
Photographic evidence:
For years now, I have tried to envision a way to get my FJR's GPS mount up in that same general area, even to the point of considering drilling mounting holes in the windshield itself, but have not come up with a good fix to date.