MM49, enjoy your ST tires.  I think we've all seen what your agenda is here.  If you like them, that's fine, but your argument that LT tires are not appropriate is not very convincing.   You do realize that you also have to consider what the axle is rated for don't you ?
I would suggest to new folks looking at this whole subject, go crawl under your trailer and see what your axle weight capacity is.  Also, consider your wheels.   In order to get into a 15" wheel that will carry the load that an LR E tire would support, you are likely needing to have a 6 hole, 15" rim.  Some are, but many in service on RV's and horse trailers, are 5 hole wheels.   It's a "system"....it's not just one component.