The chief administrative officer shall prepare the preliminary budget in detail, making any revisions or additions to the reports of the department heads deemed advisable by such chief administrative officer. At least sixty days before the beginning of the city's or town's next fiscal biennium the chief administrative officer shall file it with the clerk as the recommendation of the chief administrative officer for the final budget. The clerk shall provide a sufficient number of copies of such preliminary budget and budget message to meet the reasonable demands of taxpayers therefor and have them available for distribution not later than six weeks before the beginning of the city's or town's next fiscal biennium.