Tires on trailers aren't as sensitive as the same tire on a tow vehicle to issues (not all) like proper tire/wheel width. Thats why LT245/75 has always worked fine and why folks that have used them don't have issue .... like they would on a truck.
Unlike the same tire on a truck, those tires on the trailer will operate 24/7 at close to their max weight rating which eliminates issues like riding the centers and other issues we would have with a same tire on the tow vehicle.
I've worn out several sets of LT245/75-16 E tires on 6" wide trailer wheels on my equipment trailers. I got the same 40k-60k miles out of them just as the LT235/85-16 E tires.
I prefer a narrow tire like the 85 series tire for trailer use. If it was my trailer the first choice would be the LT235/85 but if there wasn't room then I would go with the LT245/75 tire. They will work fine.