Hello,

What are people using to attach the aftermarket foil lines ( the steel rings instead of chicken loop ) to traditional harness?

what kind of QR?

I use the Ion rope spreader bar, paired with a metal V chicken loop,
I use North Navigator, but I know duotone and a couple of others offer one as well.

The Ion has a click in quick release which makes it fast and easy. You can purchase in various widths to suit your harness / hip width.
I have added a 2nd thinner safety which is slightly longer so if the main rope breaks I have a chance to get back to shore.
I also have a stainless ring on there in case I want to use another bar.