The charter form of government shall be specified in a proposed charter written by a charter committee. The proposed charter shall establish an elected legislative body. The charter shall specify the number of members and term of office pursuant to section 331.238. If the administrative offices of the county, excluding an elected county executive, are appointive under the charter, the board shall have at least five members. The charter may establish legislative or administrative organizational structure. The charter may include the provisions necessary to permit an orderly transition to the charter form of government. However, the provisions shall be limited in scope consistent with the intent of, and in accordance with, section 331.238.