In jury eligible trials within the jurisdiction of this court, the jury shall consist of six persons but may also, by consent of both parties, consist of three, four, or five jurors. Jurors are subject to challenge for cause, which challenge shall be tried by the court. At the time set for a jury trial, the list of potential jurors summoned shall be called and shall constitute the jury, unless excused or successfully challenged, in which case other potential jurors sufficient to complete the jury shall be summoned. If the court finds good cause, one or more alternate jurors may be chosen.