I've been looking into tires for this thing.
I've got 4,000 miles on the stock Pirelli Phantoms and reports from the RE forums state that they won't last more than 6000 miles.
I'm not interested in experimenting, I'd like to find something in the stock sizes. 100/90-18 and 130/70-18 rims are 2.5" and 3.5"
For around $250 USD I can order an in-stock set of BT-46s and have them in a few days. Those should more than handle the task.
Shinko 712 rear isn't an exact fit so those aren't an option sadly.
But if I want something better off pavement, so far in my search I'd need to stray from stock sizes, or run a mismatched set, which I'd rather not do.