Rated shackles and Reece towbar

I suggest that if the pin of a rated shackle will not fit through the hold, neither will a hammerlock. The bulk of the joining bits of the device are as large as the bulbous ends on the shackles.

That's exactly what lots of people do. The HR towbar on my Pajero has quite small holes, whereas the HR fitted to my Maverick had large slots. Even after fitting the biggest hammerlocks that would fit through the holes, the shackles I had been using with the Maverick wouldn't fit through the hammerlocks, I still had to buy smaller shackles. The hammerlocks make it so much easier.

The issue with permanently fitting any device is when not in use it should be secured so it doesn't swing around because most people don't think about wear on the pins at all or simply dismiss it because they don't know any better. It will reduce its load rating faster over time because any lifting equipment gets downgraded when there are any signs of wear doesn't matter if it's being used for lifting or towing. I have always removed shackles but see lots of people still driving around with them fitted I worked around cranes and lifting equipment for 20yrs so maybe I'm more cautious especially when towing. Shackles etc should be regularly inspected and replaced when needed, these days there should be info available on the net to help you with how to inspect them.

Even funnier is the concern of using rated shackle and then they overload the rig with enormous vans, tinny and outboard, bikes, fridges etc etc.

Some of them don't even fit additional towing mirrors.