From an engineering side, lock washers (split washers) are useless. Space and Automotive industries have been slowly phasing them out after NASA’s research showed no benefit over a properly torqued bolt.
But, for our use case here, it’s up to you, you’re not going to hurt anything using them.
I vote winch, as I just installed mine on a DIY hidden mount. Weight isn’t bad with synthetic line (plus the safety of synthetic trumps!). There’s always an anchor option, you’ve got a great big anchor out back with the spare tire that you can bury in a hole with winch line attached. Also a...