I just finished the IDBDR in July on a 2014 R12gsa and one of the guys in my group was on a SuperT. The SuperT did great. He had a new set of TKC80’s. I would recommend as aggressive a tire as you can find. IMO something in the neighborhood of the TKC80 or Mitas E-10 is ideal. It just makes the route that much more enjoyable/doable. Especially if you hit any adverse conditions like rain, etc. The majority of the route is gravel but there are sections of loose shale, sand, ruts, rocks, so you can never let your guard down. Complacency is the biggest danger on this route. A good tire gives you that extra buffer of traction IMO. Best of luck, you’ll have a blast!