Powerbouy, I have used this method and have had good results. I used a two part, hard neoprene rubber for the center 1/2" bearing holder. Then epoxy to the outside edge. I also have some neoprene wheels done this way, rated at 200lbs. Finding dead center is going to be your challenge. If you could rotate the plate on it's own bearing and true up the outer edge would make it a lot easier
Joseph.