I'm also considering going to a G tire. My problem is that my rims are 80 psi rims, and it's hard to find 16 x 6.5 rims in a 6 lug pattern. Most of the high pressure rims are 8 lug.
However I think I've found some at etrailer that will work. I'm still researching.
Amazon did have the G614 tires for $272 each, but they are now over $300. Simpletire.com has them for $272 plus $23 shipping, so after buying high pressure valve stems, you're at $300 per tire plus mounting and balance, which usually runs $20 - $30 per tire. So, a set will run aprox $1300. Just wherever you buy them, check the date of manufacture, just to make sure they aren't 3 years old at install. Tire suppliers like to get rid of old stock. We don't want to start out with old but new tires.
2016 Ford F-350 Lariat CC, 4x4 SRW. B&W turnover with extender. 2015 CC Silverback 29RE, fitted with Reese Goose Box. Amateur Extra Class K5TS, 2016 nights camped 16