I have one almost identical to this at our place. One thing I’m going to add is a short piece of towing strap anchored to the concrete directly below the skinner. Use a pair of vise grips to attach hide to strap while lifting carcass leaving the hide on the ground. You’ll have to readjust it a few times during the process.
Didn’t see it personally but someone told me they did something similar and says it works great
They took a disk blade with a chain through the center and put it in the concrete when poured. Had a S hook on the other end that you could hook in the hide