Not OPEN open, spec the duro, leave the brand open. Big difference.
And if you spec a tire that doesn’t grip virtually the same over its’ full lifetime then the person with less heat cycles has a better tire — same dilemma even with a spec tire — the rich will buy new ones every race, the budget racers will be stuck…
Whereas if you just spec the duro, I can check it myself and run whatever I want.
Though I no longer have them, at the end of the STARS! WKA event at BeaveRun in 2001, I collected 92 tires from the trash bins, plus some bodywork. I matched the tires by brand, size, and condition, tested them with a durometer, and didn’t buy another tire again for the next 5 years. That’s budget racing.