Car Dollies Needed....Make or Buy??

I’ve got a set of the HF dollies. Well, actually two pairs, one set of the curved black ones and one of the diamond plate V style. They both work fine on a shop floor or even a concrete driveway as long as it’s relatively clean. Obviously the wheels aren’t that big so they don’t do obstacles or uneven surfaces that well. But that’s just common sense with a smallish caster.