Proceedings for the incorporation of metropolitan districts shall be originated as follows: Any city, village or township may, by a resolution adopted by its legislative body, have prepared a description in general terms of the district proposed to be included in a metropolitan district. Each city, village or township desiring to become a part of said district shall thereupon by appropriate resolution of its legislative body indicate its desire to become a part of same. If a part of a city, village or township shall desire to institute said proceedings or become a part of any proposed district like resolutions may be passed by the legislative body of such city, village or township upon petition to its legislative body signed by not less than 5 per cent of the registered voters in said part of a city, village or township. In said resolution or any subsequent resolution the legislative body of each city, village or township shall designate a person as its representative on a charter commission: Provided, Any city now or hereafter having a population of 50,000 or more inhabitants as determined by the last federal decennial census or by any federal decennial census hereafter taken shall for the first 200,000 population be entitled to an additional charter commissioner for each additional 50,000 population or major fraction thereof, and for all population above 200,000, an additional commissioner for each additional 100,000 population or major fraction thereof. Said commission shall thereupon meet upon written call of any of its members at a time and place to be designated in said notice and elect a president, a vice-president, a secretary and a treasurer and such other officers as it shall deem necessary. The commission shall thereupon prepare a budget of the expenses to be incurred therewith and shall apportion same to each city, village or township upon the basis that the total assessed valuation each city, village or township bears to the whole assessment of said area. Each city, village or township shall pay its representative or representatives the sum of $5.00 per day for each day of actual attendance at meetings of said commission: Provided, The total sum so paid each commissioner shall not exceed the sum of $500.00. The legislative body of any city, village or township may from time to time fill any vacancy existing in its representation on said commission. The members of said commission shall take the constitutional oath of office before the county clerk. A majority shall constitute a quorum for the transaction of all business. The legislative body of any city, village or township may, by resolution, express its desire to be included in said district at any time after the organization of the commission and the commission is authorized to take such action thereon as in its judgment is deemed advisable.