As the driver of my team, adding a second driver means that you have to forget what you’re used to and learn to cooperate with the other person, which takes a lot longer than just to practice driving.
If there isn’t a lot of buttons to control (ex. a complex tray), using a single driver also reduces the reaction time between driving.
If you are using the tray macro, consider checking out this video. Their puncher angler will automatically go to the other position when the button is pressed. The same can also be done with the tray macro. However, I will still suggest including a manual tray control since a lot of things can happen while stacking, so making the driver able to adjust is a good thing.