Acme Tow Dolly

I have used my Acme for one season it seems to work just fine. Have not had any experience with other dolly's. The only thing I see on other models is there seems to be a somewhat hollowed out area, where the tires sit. I have found a method after some trail and error strapping the car down, but now have a system that seems to work for now. It is hard to get the car on the dolly perfectly (squared) lined up. But it seems that a hollowed out area would locate and possibly lock the tires in better. I do like how light the Acme is and is easy to move around and that it stands up in the garage against a wall and out of the weather.