Research that hf winch. I was set on getting one for a fencing project until i started reading reviews. Buy cheap...buy twice.
As far as your plan to mount. I'd mount the winch plate to the bottom of the stud wall and the top of the concrete and with a big enough mounting plate to spread the load over 2 or 3 feet. Attach to both and spread the load and it should be fine. Probably not needed, but I always over build stuff so I don't have to worry about it.
Be nice to see a reverse pict towards the wall showing your line of action. My feeling as a retire structural engineer is the two bolts holding the hitch are the only ones actually holding the load. The rest are holding the board up. If those two give out the hitch leaves, possibly with vigor.