Thanks, I had been wondering about fabricating one, but it'd be nice if it was a propper thumb screw.
I played around with Google Earth yesterday. Pretty good. It actually loads maps straight from the Zumo now, so you don't have to convert the files anymore.
I couldn't really work out how to edit a route effectively (wanted to ammend something I've Thanks for the tip on the screen protector. Where do you get them from?

As for not using the screw. I've read quite a few horror stories of the zumo jumping out of the cradle when hitting a bump (bye bye zumo) when not using the screw. That's why it's called a security screw, nothing to do with the safety of the unit (it takes seconds to remove the cradle from the ram mount).