I belive they also tend to set the castor different on one side to counter the camber angle of the road. The last time i got my ke70 wheel aligned i told them i wanted them the same, and they did, i didnt notice any adverse effects. Didnt notice any advantage either, so ive never bothered with it on any of my other cars.
With -2 camber +2 castor should be pretty good i would think, especially for steering wheel weight, just might need to watch your inner tyre wear.
See how you go though, castor is adictive, you might find yourself wanting castor with less camber due to tyre wear. I was up at around +6 castor i think, with -1 camber. (i had s13 camber tops in mine, which gave massive castor at moderate castor arm adjustment while keeping the wheels centred in the wheel arch.