That is the "proper" way to do it, imo. I put "proper" in quotes because there is really no right or wrong with suspension tuning. But the problem with sways is the lateral load transfer that occurs. It transfers load from the unloaded inside tire, to the already overloaded outside tire...decreasing overall grip. Atleast when you use the coilover to control roll you do not decrease grip. Sways are used to fine tune the balance of the car.
I don't know whats up with all these really low front spring rates for MKiii though. It's like none of these companies have done the necessary legwork and figured out the installation ratio and roll rate. I'm running 23k/12k and the balance is perfect. And no it's not too stiff. With properly valved dampers the thing rides like a Cadillac, but body roll is really well controlled.