On a different note, since we are talking CRR, here is an interesting article:
https://blog.silca.cc/part-4b-rollin...-and-impedance
It shows the difference between the theory of drum tests vs actual riding on the road (where what they call "impedance" also starts to play a role). There are a couple of interesting take-aways that I see here:
1) It is better to err on the side of tire pressure being a bit too low vs a bit too high
2) Tires with more supple casings tend to have lower CRR and also more forgiving of over/under pressure
Does that level the playing field in the rear world, for tires like Turbo Cottons, which test 2-3W slower than GP5ks in the drum test but have a much more supple casing?