Just reading up on legality of hooks. The above discussion is 15 months old and I'm wondering if anyone is actually using clevis hooks these days. Reading the NT requirements (easiest state regs to read), I suspect that clevis hooks (with latch) are legal as long as they conform to the strength parameters. Shackles & Hammerlocks are specifically mentioned but also implies anything that conforms is OK. Clevis hooks are used for vehicle recovery so I'm thinking that they are OK on van & trailer safety chains.
My new tow bar is hidden so I have to be a contortionist to get the shackle connected. I was looking for something to hook on/off easier.