kei office specialise in drift sus (Keichi Tsuchiya aka drift king).
Excellent coilovers, hard spring rates. The adjustment is as you thought, with a small screwdriver, they use a KYB insert that has 4 levels of dampening. Adjust too soft, they get bouncy, adjust too hard, and the wheels may loose contact patch.
For the street, I suggest you run a 3 in the front, and 2 rear. If you find you are understeering, try backing off the dampening, oversteering (and you dont want to) back off the dampening rear.
Somewhere to start anyways.