You cant go wrong with the Hankook's. They are a tire that meets all the requirements for a Vanagon/Westy. Since we basically ride in a "loaf of bread" on wheels, the 8 ply sidewall is a needed safety factor. Most L/T and passenger tires dont have the extra plys. I installed a set just yesterday and they replaced the Yokohama Y356 I had. So far I can say that they seem to ride smoother and handle better than the Yokohama's did. The Yokohama tires are a reinforced 8 ply as well and are fine and safe to run on a Vanagon. Your choice....and hats off to you for doing your homework B4 spending your hard earned money on a tire thats not designed for our particular "loaf of bread".
I would highly recommend Nokian WR C Van tires. Great side wall profile and is All-Season. I have a 90 Westfalia GL and was searching for a tougher looking and performing tire without getting into an All-Terrain. The Nokian WR C rides well on all surfaces and it is comfortable and quiet for highway driving. Great in mud and on wet grass too. Exceeds VW Westfalia weight and ply requirements. Have 20,000 miles on them and they are wearing nicely. Enjoy your Westy!!!