Thereupon the county board of such county shall take to its assistance the county surveyor of the county and shall determine whether or not the boundaries of the proposed district are reasonable and proper, and if the board finds that the boundary line of the district should be changed, it shall change the same and fix the boundary line where the same, in the judgment of the board, should be fixed with a view to promoting the interest of the drainage district, if formed, and with a view to doing justice and equity to all persons. Anyone asking shall be given a hearing as to the boundary. The board shall also determine the number of directors that the district shall have, if formed, and the amount of the bond to be given by each, and shall make a record of its action.