I had the Valentine one and Concealed Display hard wired this week. What we used was the visor clip. Turns out it slides nicely behind the liner and it exactly where I wanted it mounted.

I freaking love this toy.

 

When I used to have a V1, if you had the black headliner, it has a felt finish, and I placed a velcro on the concealed display and ran the cable up top, tucked in the liner. With the visor down, you could still see it perfectly as well.

 

Very cool.