Does anyone know how to make a Hobie Outback Plugin Cart?

I found a Wheelez Cart "Mini" for $110. Are the Minis just as good as the full size one, for my Hobie Outback? It's a better price for me just wondering how much of a difference it would be. For now I'd be using it on hard surface to get from my car to the boat ramp, but later on when i go into the bay it will go through sand or some rocks.

Any advice is appreciated. I want to get out on the water this weekend! lol