Such charter commission shall prepare a district charter providing for the administration of the property and affairs of the metropolitan district. The functions, services or works to be performed by such district shall be determined after an investigation of the needs of the district to be formed and after public hearings held for the purpose of obtaining the views of the electors. The members of the charter commission shall serve without compensation but any expense incurred in the discharge of its duties shall be paid by each town, city or borough to be included in the proposed metropolitan district in proportion to the percentage which the population, as determined by the last-preceding federal census, of each participating town, city or borough is of the total population of such district. The charter commission may engage such employees and contract for the services of such consultants as it may need for the proper execution of its duties.