Yes, there are 4 turning blocks on the rear beam (shown as black ovals and attached by some small line to the tramp tension lacing). There is a block and a D-Shackle at the center position to allow multiple lines to run through and up to the Dolphin striker.

For the rings, I'd go stainless, large diameter (~2cm).

BTW - really sorry - didn't see the single-line system comment until now. Realize what I have provided is not very helpful...