I also tried that but, and this is a controversial topic of course, I think there may be a catch. The V650 already seems to suffer from the fact that not enough air is flowing from under the windshield, so there will be a vacuum which will be filled by updrafts and so on, the whole buffeting shebang depending on which screen you have yada-yada-yada. So putting your phone holder in that area only aggravates the problem, air moving up behind the screen is disturbed so air from other places will get sucked there. But this may only be a false impression, I will at some point re-install this holder and try to use it again, because the heads-up aspect of the navigation is very important too.
Another issue is vibration. While the handlebars are very stable, the whole nose cone with the windscreen is not and this style of mount amplifies the vibration problem, because it brings a beam out of the epicenter, stretching the amplitude of the oscillations. This will result in blurry picture and perhaps will damage the accelerometer and similar components in some phones. Then again, it may just as well work out fine for someone and be very usable. You know, just like the clip style chain links that never fail in a lifetime for some riders but the first time I try to use one, an instant shitstorm ensues.