So for the guys running P-zero take-off slicks, how far are you running them down before you decide they are junk? Until the wear indicator holes are gone? Down to cords? Mine are getting down to 2/32 on the outer edges and 3/32 in the center. I have new P-zeros and the wear holes are 4/32 deep on my depth gauge. Seems like my current tires should last another couple track days as they still have grip. Thoughts?