I have two used Michelin Pilot Supersports for sale. Production date for both them are the 29 week of 2019. The tread depth is around 6/32 for both them. Just for reference, new they are 8/32. Also, the tires have never been plugged or patched. I'm asking $390 obo.
I recommend the blanket heatsheild as a last resort before going to a a dedicated cooler. I've been having a lot of success with it. Check out my post on this thread.
I was doing some gearing calculations on Tremec's site and this is what i got based on the stock PP2 tire size 305/30/19 (26.2") with 4.09 gears. This rearend and tire combo will get you really close to 15-17 gearing.