I have done my events on 28 tubeless so far; but have some 30mm Goodyear tubeless am experimenting with currently. So far so good. Might even go crazy and try 32 next
Always use tubes for road.
GP4000 28 come up at 31mm on 18mm rims. 28mm Pro 4 Endurance are true 28mm. GP5000 have even thinner sidewalls so dismissed them and I've tried TL version with tube. No fucking way would I want to try and work on those in the field during a race.
I have done my events on 28 tubeless so far; but have some 30mm Goodyear tubeless am experimenting with currently. So far so good. Might even go crazy and try 32 next