Who told u wearing a watch would bother your elbow? Never heard that before. I use a watch and love it.
Phone apps have a bad rap for draining your battery so i have never bothered with one.
I also have a rangefinder. If im in a cart it takes 2 seconds when you next to the cart to laser and then put it on the seat. If your friend has trouble hitting the target ( mine is an old unit and is tough as well) do what i do and laser to someone putting near the hole. If nibody is on the green laser it to traps etc..