Such commission shall be by the Supreme Court called from time to time, and shall only be required to remain in session such length of time as is required for the hearing of such cases and conferences concerning decisions and conclusions to be reached, and in the designation of the personnel of any such commission or commissioner, the Supreme Court shall take into consideration the question of the necessities and the good of the judicial service to the Supreme Court and in the several counties of the state of Idaho; the Supreme Court shall make designation of appointment, substitution and transfer of judges with the idea in view of minimizing expense, and neither such commission nor the commissioners shall be required to remain absent from their respective districts for a longer time than is actually required for the proper performance of the work of such commission in aid of the Supreme Court.