I prefer the wheels with a substantial axle - CatTrax or the EuroTrax.

The way that I put the boat on the wheels when singlehanding is (with the boat on the ground or beach), start the wheels under the bows (this is tricky on boats with large plumb bows a not a lot of rocker - really easy on an H-16). Once the wheels are started, you can usually shove them back by pushing on the center of the axle. Once you can reach the dolphin striker, you can pull on it while continuing to push the wheels aft using a foot (or two) on the center of the axle.

I can get my Tiger up on it's wheels in about 15 seconds using this method. With no assistance.