Close up of the level. Note I've used screws to secure the level to the side of the PUP. Using the foam backing is not adequate as the level will move with time.
I've added levels to both corners sides (front and side) of the front of the PUP. This allows me to quickly see what adjustmenets I need to make to level the PUP. Note - I have another pair of levels mounted on the other side of the trailer.