I wouldn't run so much stagger on this car on the track. Also check for play/compliance in your suspension. If you have rubber bushings, they can be suspect under load. I had some real strange tire wear issues on another car and they all went away when I switched to GC camber plates (at ran about the same static camber) with spherical bearings. You might also be forcing the car to push by carrying to carry too much speed into the turn or not using the brakes effectively to keep the fronts loaded. R6 is a sensitive tire; doesn't take much to destroy it (ask me how I know!) Finally, you might want to check this out:
http://www.tirerack.com/images/pdf/warranty/HOOSIER.pdf