I personally dislike the "dangling chains" that seem quite common. First, I don't think that 1/2" bolt spaced out like that will stand much of a pull. I notice some folks use those hardware store quick repair links. If you ever check the specs on them (some have them printed on the label) you'll find most of them very lacking.

I buy weldable chain hooks. Mostly 3/8, Gr 70. They are made to be welded. They have no eyelet on the end, only a hook for the chain. Then I weld them to either 3/8" or 1/2" plate, depending on the tractor size. You find 2 bolt holes in the tractor frame about 4-6" apart & drill that plate (actually, drill first, then weld) and bolt it to the frame with whatever size bolts the frame will accept. 1/2" Gr8 bolts should handle most tractors. One on each side of frame. A friend of mine in the welding business said after he saw them, "if you ever roll that trailer with the tractor, the chains, hooks, and part of the frame will still be attached......the rest of the tractor will be scattered

You can use binder chain, or ratchet straps to drop into the chain hooks. Both work. On the rear, we'll sometimes use clevis, but it usually bends the drawbar down. If it's a horshoe drawbar (IH), we'll often use the chain hook hitch bins available from Shoup. 

Here's a photo of an unpainted hook on our IH 400. After they are painted, they look completely like part of the tractor. Check the bottom photo. Once  you get done admiring the handsome Mr. Greif, then look for the hook on the 400 bellhousing.