I bought the "red" ones from Speedway and love them. If the car is heavy, make sure you have the casters all pointed the same way. Sweeping the garage floor is a good idea. I've welded jack stands to them and recently I bolted a Y Block floor stand to a couple.
I move my 51 Fordor around by myself, but it is a chore. Roy

Life isn't about arriving at the end in a pristine, well preserved body; It's about sliding in sideways, all clapped out, yelling "What a ride!"