The summons may be served by publication as to any defendants who cannot be personally served, as provided by law. Such summons shall be returnable to the first day of any regular term of the circuit court of the county, during which term, or some succeeding term, the court, after determining the sufficiency of the petition, shall immediately enter of record three interested resident freeholders of the proposed project in which the lands are located who have been elected by a majority of the petitioners. Such persons appointed shall constitute a board of viewers who shall select and designate an engineer, or other person experienced with drainage, deemed qualified by the board of viewers to make a preliminary survey and report thereon. After the appointment of the board the question of the sufficiency of the petition may not be again raised, unless the boundary of the district be subsequently changed by the court.