I’m not a rigger either, but I think the you should use a shackle with load rating that is similar to that of the hanger wire cables you installed. And use a good quality stainless steel marine shackle.
And, I would also, if you haven’t already, attach the split ring on the shackle such that it is also through the shackle loop thus preventing the pin from working loose. Usually that is easier done with monel wire. Then wrap the shackle and nico press fitting (especially at the bottom end of the hanger) in rigging tape so that any sharp edges don’t slice the sail.