Im not gonna go back and research the whole thread, but in my opinion, an 18" with the same wheel as the tow vehicle would be the most reasonable answer. 18"; is pretty common for truck rubber. Lots of options.
I'm pro LT. Once you start spending money for quality, radial ST tires, you will realize that truck tires will do the same job, but with a bigcost savings.
said, worn down LT tires seem to work just fine for jack knifing tandem trailers. I do the same and have never had a bead pop off. I even use a skid steer to move tandems. You can turn trailer around in Its own circle with a skid steer. I've left lots of scrubbed rubber on the ashfalt. Never popped a bead. I don't buy the stronger sidewall bull shit of an ST tire.
Like that has been answered already, as long as you are not commercial, there will be no issue being over weight by a couple hundred pounds per tire. Once you admit you are hauling for pay or trade, all bets are off.
I need to admit to you guys, this is my first night off in a week. I've had a few drinks. I won't apologize, but you need to be aware.