This response is for Scott and any one else that might be wondering about this install. I replied to your email but noticed you had a "military" address. I have a couple of friends with .mil addresses and sometimes my emails get sucked into the big military cyber black hole. Anyway, wanted to make sure you got it so here goes:
I bought the shelf from Cyclegadgets here:
The pictures that they show do not show the brace for the left side of the shelf, you will need it. Without it you will have a LOT of vibration but with it it's minimal. Not entirely gone, but minimal. I've got 13k on mine and it's only annoying on really bad roads. Don't know if they have it yet, they should. But you can also contact Mark at Big Mak Accessories and he will take care of you. He has a pretty cheesy web site but his product is good. You could also buy everything directly from him. I didn't know it at the time of my order or I would have. Either way you can't go wrong. Just make sure you get the brace.
The shelf replaces the plastic piece that's stock under your screen.
I mounted the Zumo dead center on a Ram mount and then the XM puck behind it. I drilled out a couple of holes to mount it dead center. If you didn't mind you could mount it off center a bit with holes that are already in the shelf. Though the pictures on that page don't show them, mine had pre drilled slots / holes. Easy to drill though. It's aluminum. I put the XM puck on with dual tape so I can remove it and put it in my truck. Also, where everything is mounted makes it almost impossible to remove if you put the screen down. There's just no room to get your hand in with the screen down. It sits perfectly snug on top of the puck and the Zumo lock. Most of the time I don't worry about either in the places I go. But even if you remove the Zumo the XM puck is tucked down in safe. It's pretty slick actually. With the screen down some one would literally have to bust the screen off to get to the stuff.
If I remember right I had to bend the brace he sent a bit to get it to fit properly. But that was a year ago and I did discuss it with him at the time. Hopefully he has the issue fixed. No big deal really, I don't think the entire install took me an hour. Now that I have seen it I could do it in 30 minutes.
As far as the placement I think it's perfect. My eyes really don't have to leave the road. At least not as much as if it were down on the bars or behind the bag. It's just right there, but not in the way. No interference with the display either. Also I have the Big Mak Tank bag and it flips forward. Easy as cake to gas up. Some guys have mounted GPS's down in front of the display dead center and claim they can use a flip up bag to fuel with no problems but I don't know how. I have yet to actually see it done. My bag would hit anything that I put there.
Lastly....I love the Zumo. Great product. You'll want a good set of noise canceling in ear headphones though if you want decent music. No earbuds or helmet speakers. They just don't cut it.
Anyway, hope this helps. Let me know if you have any questions. Post a pic or two when you're done.
BTW....thank you for your service.