I cannot speak for the 612 DaYi back; however, I have a 617 DaYi Shift II, and the back on it is fine. The beauty of it is the split pressure plate (i.e twin, independent spring-loaded plate) that holds the film flat on both sides of centre.

If the DaYi 612 has the same (albeit less wide) design, I cannot see how the Horseman could be any, let alone significantly, better.