I was looking for the easiest way to hook on to the boat and I had a set of tie-down straps lying around that have the "L" shaped hooks on them. Here's a photo of the boat hanging and you can see one of the aft attachments:
(we were wrapping it to go to a boat show 250 miles away - in winter)
The hooks have a 1" "flat" on them so there's not a point load on the inside of the deck lip.
Another consideration is the boat's center of gravity which is only about 18" behind the front crossbar. If you lift it by the crossbars, the forward lines will take almost the whole load. I wanted the load to be roughly equal on all four lines.
I also used this hoist for my H-17 - it would take me about 45 minutes to switch boats from the hoist to the trailer & vice versa. Part of that time was spent re-adjusting the trailer to fit (Trailex trailers are infinitely adjustable). I did notice that the 17's deck lips would deflect out when on the hoist, but they always sprung back.
The way this is set up, I can wheel the boat in on the trailer, get the trailer sideways in the garage and hoist directly off the trailer. Coming down, I lower onto Cat Trax, since there's a ledge that prevents the trailer from getting directly underneath the hoist. (You can see it in the photo.)