I know this sounds odd, but I used an Apple TV remote control holder. It's sticky-taped to the Roady XT mount and the back of the Tesla screen. Fit almost perfectly - not sure how else to describe it! Just have to make sure to mount it high enough that the console door clears for the phone charger. It will if you get it right ;-)
I'll do my best to snap a photo of it today from behind the display for you.
I set the Roady as my primary connection, so it hasn't been an issue. Like you said, you do have to do it manually if the phone connects first. I found that for the most part, the Roady isn't powered down when I get in... especially if I've pre-conditioned the car, I find it's awake and connected when I get in.
It's not a perfect solution, but better than what else I've used to date. And way way better than the SiriusXM interface on our Model X... Tesla should be embarrassed at the poor state of that thing. It's basically a half finished intern's summer project.