if it's barking, you're just digging grooves into the diff rings. Tighten it outside of the car to factory specs, once it's back in the car and ready to run...then start by holding one wheel and easily rolling on the gas until you hit full throttle, then back off to 0....repeat for the other tire. This will seat the balls into the rings safely without risking burning up the whole diff. Once you've done the tire thing, re-tighten the diff by hand according to the feel (hold one wheel and spur and hand turn the other wheel) Adjust accordingly. Once your diff is set, set the slipper for feel and track conditions. Generally you should have a 2 foot "whirring" sound then it will take off.
I personally like a 1 foot slip and just let my throttle finger take care of the rest of the throttle control....I don't like my slipper to feel like a current limiter...Keep the car snappy but managable.
TQ Racing Wire