I agree an actual dedicated roti burner would be ideal (thats why I have my Napoleon) but it can be done fine as in the picture below. But you will notice that the left shelf is down as the motor would not fit with it up.
I would think that having the additional distance above the burners, it would help eliminate hot spots when using a rotisserie. Still, a dedicated rear IR burner would be the way to go. Even when I had a grill with one of those, the center part of the chicken was closer to the burner and cooked more. With 3 burners and some practice, you can probably get good heat distribution.
