The included ball head will not be able to achieve a 90° angle, as the head can’t even achieve that on itself in the notch:
This is the straightest vertical angle possible with this ball head / tripod combination:
Notice that the PPM is resting against the tripod legs.
Not being able to reach full 90° tilt isn’t a big deal as you can then correct the keystone with the 4 corner correction feature.
I tried to use another ball head on the same tripod, with much better results, although I had to set the ball head to slightly less than 90° due to the fact that the legs had flex in them meaning that they would sag due to the weight of the PPM which would pull them past 90° if not for my correction in the ball head:
Here you can see the PPM is not touching the legs.
hope this helps anyone wondering about this.