The OEM R4s on my Kioti handle 40 psi, and a load cap of something like 2000 lbs each. But I also have 1500# of counter-weight.
My loader is only rated at about 1150#, but that's at full height. I can lift a full ton a few inches off the ground, and do so regularly. The JD 420 or 430 loaders have decent load caps, too.
i would say the capacity is nearly the same as yours. something like 1200 at full height, 1900 at 5' and 3000 breakout. i'm not sure the load ratings on some of the tires are even accurate. 1 saw one place listing a 6 ply at 8000 lbs. that seems suspect considering most of the other ones were more like 2200 lbs. i'm sure the loadmaxx ones will be fine, just wish they would show an actual weight figure.