Just one more aspect to Large Flap Settings: the CG
I haven't flown my Hawk yet, but a far forward CG (nose heavier) might seem more stable but this can have a negative effect when using large landing flap settings combined with slow speeds.
Because of the forward CG, a change in pitch requires more stabilizer and when flying slow, even more stabilizer is needed for a pitch change.
This combination could mean that the Stabilizer might reach it's stall limit.
Another reason to first test this high enough and when feeling assured, use max land flaps when established on final and in a steady descend with sufficient speed and thrust.