On my 67 I am running 29x12.50x15 Sportsman Pros, They fit fine, but to answer sydcuda's question, Yes, I have a 1" plate mounted between the front spring hanger and the frame, works good!
Any chance of a pic or 2, or 3 of that tire set-up? I am looking at the exact same tires on sale over here and would love to get a sneak peak at how they'd look. I can see from your avatar pic that they look mean, but a large pic would be great if possible. Thanks!