In all proceedings under this article, it shall be expressly permissible for the parents of a child to agree to binding arbitration on the issue of child custody and matters relative to visitation, parenting time, and a parenting plan. The parents may select their arbiter and decide which issues will be resolved in binding arbitration. The arbiter’s decisions shall be incorporated into a final decree awarding child custody unless the judge makes specific written factual findings that under the circumstances of the parents and the child the arbiter’s award would not be in the best interests of the child. In its judgment, the judge may supplement the arbiter’s decision on issues not covered by the binding arbitration.