There is a correct mounting for that sensor. It has an arrow stamped on the sensor that has to point up. It also says in the manual it should flash the LED when tipped (and I assume) also when the door is opened and closed.
Sometimes it is better to mount the sensor higher on the door so it reacts better.
And metal shouldn't really affect it. It is made to go on a garage door so that would be really silly if you couldn't mount it on a metal door.
And far as I know there are no user dash templates. You can request to have a different one, but adding a new one that (essentially) copies the function of an existing one is probably not very high on the Hubitat team's priority list.