grnspot I use a setup similar to yours. Sometimes with a heavy log I have to put the dolly on the log upside-down, and bind it onto the log, then upright it (tip it over) with levers. Then hook onto the front with the log arch and drive away. For that reason it's good if the dolly doesn't have a wide stance.
plumbstraight I like the dual use of yours. The 'arch part" looks is a lot 'skinnier' than the arch that I got from Northern tool (which is mean to be used by hand). But the drawbar pulls directly on each wheel. I'll have to think about that for a little while?