To get the log on the dolly I used a loop of rope around one end of the log and a heavy duty bumper jack to lift one end of the log about a foot or so off the ground. I then rolled the dolly under and lowered the log . Cant hooks and a few 2x12`s would work nicely too. The dolly is only 7 or 8 inches high so the ramp angle would be small.
If you do build one of these make sure your wheels are heavy duty equipped with ball, preferably needle bearings and grease fitings. 1" axles are a must. Tires must be able to hold at least 70psi because the contanct patch is tiny. Its rolls good on hard ground. Soft ground fahgitabahdit with a heavy load.
The steering is a sliding plate design. Basically two peices of 3/8ths steel plate with a 3/4" grade 8 bolt thru the middle and zerks to keep a lot of grease between `em. Top plate goes to the front wheel assembly bottom to the back. Pivot point 1" aft of the front axle axis.
My next step with this is to install removable stantions....sort of like a bell-hop cart so I can stack a pile of branches and haul them out to the curb/chipper.
Good luck ,
Glenn Gertis