I purchased four of the Sternmaster pontoon dollies. They came partially assembled. They look to be excellent quality. The frame and casters look like they will support my pontoon quite nicely. I will know more this fall once we bring the new pontoon in for storage. I won't know before then because the dealer will deliver the new pontoon and put it in the lake for us immediately.I store my pontoon over winter in a storage barn with concrete floors. What does Bennington recommend to use as an easily movable set of four pontoon dollies with large swivel wheels so the pontoon can be moved easily around the floor. (The pontoon has ultralegs/sealegs. These make it harder to load using a scissors trailer. Thus, larger wheels are needed to ensure the trailer can slide beneath the ultralegs/sealegs.) Pontoon is a Bennington 2023 20LSR.