Steve,

Thanks for the link. Had a look.

I think your design is OK. The horizontal force at the top of the post
is quite small, about 1/3 of the vertical load.

My only concern is that you welded to a structural bolt (SAE Grade 5 or
8 slewing pin bottom, and top?). For lifting / hoisting stuff this is a
no-no since welding screws up the heat treatment. Too rapid cooling
would make the bolt steel brittle, and the bolt head could snap off at
embarrassing or dangerous times! I'd re-think that detail. Other than
that it looks ok.

Wolfgang