I have a set of old Pro Wedge II, now known as the AMS Zipper, that I had on my old 200x for use in snow. I had them mounted on some rims for the 350 and they work awesome in the snow. I then tried them in the dunes and was suprised at how well they worked there too. If you are in an area that gets a lot of snow you can kill 2 birds with one stone with these tires.
What ever you choose just be careful not to over paddle the 350 or you will not be happy with its performance in the sand. The zippers paddles are a little shorter so they work well.