Safety margin on tires isn't a bad thing is it?
Remember all it takes is one bad day to wipe out the cost of the tires fixing your rig.
I have a good home for my 2 year old 15" Goodyear Tires and wheels on another lighter trailer that stays closer to home. I plan to upgrade wheels and tires to 16" LT's this year on our 30' Arctic Fox with 5200# axles. I know it might be overkill but I look at it as additional insurance.
It sounds like 15" Maxxis or the new Carlisle's would be a good alternative if you don't plan to keep your rig long-term.