That's an educational site. I'm no engineer but I have two thoughts. First, if you wanted to go with the plate idea a 14 in plate with 3/8 in wedge anchors 3 in deep would over 3000 lb per bolt, not sure if you get to multiply by 4 or not. Second, it would look like you could go with something like a 3/4 in wedge anchor at 8 in to tap into the second layer of concrete on one side and 5 in on the other. That would give you about 10,000 lb and then thread an eye nut like this
on the end, providing the threading is compatible.
On second thought that's probably way to over engineered. If my amsteel suspension is good at 1600 lb anchors in that neighborhood should be good too. 1/2 x 4 in wedge anchors with the lifting eye nut would be limited to the 2150 lb strength of the eye nut. That would give you an almost 10:1 safety ratio.