AND - of course there is always the cheapest insurance - esp for a 4 post - available at your local Home Despot or Lowz or similar
Pick up 4 jackposts - the kind that support the mainbeam in many houses - put one under each corner - they will hold up to a zillion pounds each . The ones I use are rated to 8555 lb each, so 4 of 'em will ensure the whole shebang (she do?) won't come down on me, no matter what!
Just set the sliding parts to the "best size", put the big pin thru, then screw out the top part to get a snug fit between floor and the underside of the hoist.
Even the cheapest ricer hoist can hold for a long time if it isn't actually supporting anything!
I use'em even tho I have industrial hoists - cheap insurance!