Relative seniority is the much more likely scenario. It's highely unlikely DOH will happen. Basically both of the respective NC's would have to sell out their pilot groups. DOH has way too much inconsistency throughout the group, and relative seniority keeps everyone within the same area on the new seniority list. Also, if the method is agreed upon by the NC's lawsuits are a waste of time and $$$. Just ask UsAir. If the NC's agree to a binding arbitration, everyone is stuck with the result, hence the binding part.