IMHO either you need the flight nav, or you're familiar enough you don't need it anymore, unless you need to just periodically check, in which case you can just turn it off, and check when you do, so you don't have to shorten it, (again, in my opinion!)
If you "emote loudly", you can then spoof and they'll hear it in the backseat too. But it is a bit of a bummer that you can't look at the back seat in all vehicles.