So what axle is one going to use these Greenball tires and wheels on. Their rating is beyond a six lug 6K axle. Getting a higher rated axle in a 6 lug hub might be difficult. Is Greenball going to build axles for them rated to 6400 pounds with six lug hubs. We then need to look at the brakes that fix inside a 15" rim and are good for that kind of towed weight.
I have long been a fan for an all steel ply trailer tires. Which provide low rolling resistance, and lots of strength in the carcass.
You have however have down talked them over the years. Why the change in heart now?