I autocross and therefore I change wheels frequently. I also use snow tires on the street vehicles. Here's what I do, based on knoledge gained from the autocross mail list discussions on the topic, plus my own personal experience.
First, anti-sieze on the studs is a good thing. It reduces the chances of snapping a lug to near zero and speeds up your work.
Second, anti-sieze on the mating surface is not recommended. I'm not sure why but it just isn't necessary in my experience so I just keep that clean.
Third, for torque, I never heard of anyone having trouble using factory spec torque while using anti-sieze. The problem with warped rotors comes from overtorque or uneven torque. I've had both, and usually just re-torqueing cures it - its not permanent in my experience. The consensus is you can use less than factory torque, but there's no authoritative factor. Personally, for safety, if there's a range of torques specified, I use the lowest one to reduce the fatigue of frequent wheel changes. If there's just a fixed number, then I might knock up to 10% off of that, but this is purely a judgement call based on experience.