Magellan 1700 has A/V input underneath
Perhaps it is possible to also leave a cable under the dashboard for further use as a monitor for DVD, PC or Back-up cam... or pretty much anything.
How is the GPS satellite signal reception from that position...?
The generous sunroof helps but does it hold lock?
I was trying to mount mine over, on top of everything but there is really only one way to do it and it is your way, congratulations
How detailed is the joint on the screen perimeter... ?