I've had a set of hard wheels (Tiger Tracks) for 25 years. At the time I bought them, the extra bucks for the soft tires was too much. They do work in sand, maybe not a good as the soft ones. But certainly better than no wheels at all. For the short length of time the boat is on the round, the hard keel of my 16 has not been damaged.
Try it, you'll like it.
Agreed. We got our first set of beach wheels about 25 years ago and they were the hard wheeled ones. We thought they were awesome. Granted the soft wheels are even better, but anything beats dragging the boat across the beach. I would definitely use them. Also, the straight bar won't damage the 16's hulls. You only need cradles on boats with symmetrical hulls.