The problem tires are ST tires, not LT(E) tires. You wouldn't believe the difference in my Westlake ST takeoffs vs. the Bridgestone Duravis R250's in total weight, sidewall thickness and tread stiffness. There's no way the Westlakes should have 500 more weight carrying capability.
The NHTSA has ignored millions of poor quality ST tires out on the road with RV's, stock trailers, boat trailers and utility trailers. We're talking about saving lives here.
I've never heard of any complaint about 16" LT/E Bridgestone or Michelin ribbed tires on any RV trailer. Unless your trailer is a very, very heavy unit, the LT/E tires are just fine.
And as far as the budget Sailuns go, I've never heard the first complaint on them. They may be the only good tire from China that's good for heavy RV use. But remember few fifth wheels have wheels rated for the air pressure G rated tires are run at.