(1) Each party is entitled to four peremptory challenges, except as provided for under subsection (2).
(2) When a six-person jury is authorized by law, each side shall have two peremptory challenges. When the parties agree upon a jury consisting of a number of persons other than 6 or 12, they shall also agree in open court, with the approval of the court, upon the number of peremptory challenges to be allowed, not to exceed four.
(3) Peremptory challenges shall be taken as provided in Rule 47(b), M.R.Civ.P.