When dragging logs, you need to run a chain from the log to the drawbar(see attached .BMP). As your pictures show, if the log you are dragging hangs up on a stump or snags as you pull it around/thru the trees, all the pulling force will be applied to the toplink attachpoint. That is way above the axle and that tractor may wheelee over backwards before you can get the clutch in/hydro stopped. With a chain tight to the drawbar, the pulling force is coming from the drawbar where it belongs and the boom is only really providing the lift. As mentioned, only lift just enough to get the job done. As I recall there was a young boy killed a year or so back when he was with his dad on the tractor(not a good idea in the first place). They were pulling a stump and he attached the chain to the toplink instead of the drawbar and the tractor went over backwards when he took a strain. With the pulling force applied below the axle at the drawbar, it is far more likley that the tires will dig in or lose traction than for the tractor front end to come up as the pulling force below the axle would tend to force the front of th tractor down. I do something similar with my post hole boom to drag logs, but I use two chains instead of tongs. One chain pulls from the drawbar and the other goes up to the boom to lift the front of the log to make the drag easier.
Good Luck
