alignment #s

i have a firm feel 2 power steering box and tubbular uppers. i set at -5 camber and +3 castor. i find the steering feels '' touchy '', for example when i pass at hwy speeds i have to be delicate with the wheel cause it is easy to oversteer. it also wont turn the tires back to neutral posistion under 10mph. now having said this the car handles way better than it did with stock parts i'm just tring to get max performance with what i have.
thanks in advance