Just a follow-up to my original post....
Last weekend had Vision 81's and Toyo M608Z's in 245-70-19.5 installed on my 2015 Chev 3500 SRW 4x4...no front rubbing whatsoever (a wee bit close, but no problems). The guys at Les Schwab here in Seattle (4th ave S) did a terrific job. They're used to seeing heavy trucks where they're located (industrial area of S Seattle), so had the right balancing equipment along with a wealth of knowledge about truck tires in general.
I've put 50 miles on them so far, and the tendency to grab and follow seams in the pavement is already starting to fade. The balancing seems fine--nothing noticeable up to 70 mph on freeway.
A bit rough riding, but not too bad. Next up is a new set of shocks.
All in all, very pleased so far.
tom b.