Welcome to doing deadlifts.
Agree with kakno, rack pulls just below the knee.
Might also be worth doing slightly higher rack pulls (just above the knee) with around 105-110% of your 1RM, then dropping the pins down and doing it from below with a lighter weight. You might find you're pleasantly surprised.
In terms of rep work to improve your form, go with whatever setup works for you, but my personal recommendation would be cluster sets.
I feel that if the problem is around getting over your knees, it's a lack of strength in the back rather than in the hips. Additional work could include weighted hyperextensions etc., but for deadlifts, rack pulls take some beating.