If the end of the log is hidden behind the "skidder" plate, it can't hook on anything. This is how they build skidding winches commercially. I built mine from 3" square tube and expanded metal. 4 hooks on the top to hook chokers into.
If I had to do it over again I'd build it a bit wider and higher, other than that it works fine. Allowing room for a hydraulic winch would have been a good idea too.
As with any equipment, you need to be careful using it, nothing is foolproof.
Sean