I sometimes refer an interesting rigging thread over to a professional rigger for comment.
He sent back some comments and permission to share them.
" Thanks for sending the thread, it's a common problem with that design. I understand the thought process the designers had when using U-bolts as chain plates, but it makes it hard for the owners and riggers to attach turnbuckles. Flat chainplates are best and make things much easier all around.
In the first photo of the original rigging the Navtec turnbuckles were made specifically for this application. Unfortunately Navtec went out of business and no one, to my knowledge, is making a direct substitute. You can get custom made toggles from Hayn and other manufacturers.
The second photo, the yard "corrected" installation is the worst way to install. A couple of comments were made about the pin sliding back and forth, not really an issue once everything is loaded up. The problem lies in point loading the clevis pin and the chain plate/U-bolt. The stainless will deform and create divots in both the pin and U-bolt, leading to stress fractures and increased corrosion. We really try to avoid round to round contact wherever possible, sometimes it's unavoidable and will need to be inspected frequently for wear. The toggles the yard used are reversible. In the "right side up" orientation, with the threaded eye inserted through the strap, the clevis pin requires a washer on the cotter pin side to keep the pin from pulling through. I think someone commented they thought the pins were too long, not the case.
The third photo, where the rigger "corrected" what the yard "corrected" is the proper orientation for that installation. It is unfortunate the toggles required rebending to fit around the U-bolts, it does induce some work hardening, but I doubt enough to shorten the working life of the toggle. Another option, unless you get custom toggles, is to splay the toggle to fit around the U-bolt. In my experience this will cause the holes to be out of alignment and you can't get the clevis pin through. I've seen this on boats and the installer's solution was to use a smaller diameter clevis pin to get it to pass through and put a cotter pin in, VERY BAD IDEA.
The best solution, with that particular style of chainplate IMHO, is to have custom toggles made to fit the chainplate. It will add time and expense, but that's the nature of the beast, and less expensive than replacing all of the chainplates. "