Many HH IIs of that era came with 6k axles and the Uniroyal Laredo HD-H LT235/85-16 E with very good success. Any of the poly fabric LT E tires are hands down superior in reliability to any ST tire regardless of brand on 6k axles. Go to any RV forum or a brand specific forum and you can hear the same thing.
Poly tires like the Goodyear Wrangler HT or BFG Commercial HT or Cooper SRM II or Firestone Transforce HT make excellent tires for any trailer with 6k axles.
If your wanting the best of the best tire for any trailer including RVs/commercial trailers/etc the Michelin XPS RIB and the Bridgestone R-250 both as mentioned are a all steel carcass tire.
I wouldn't recommend anyone with a trailer that size use any brand ST tire.
Do your homework and check with some of the many other RV forums or the best is the nuwa.org for HH II owners.
http://www.nuwaowners.org/forum/