Each town, at the annual meeting, may determine the rate or amount of compensation to be allowed the collector of taxes for his services. Such compensation may be based upon statutory fees, a fixed compensation in lieu of statutory fees, a fixed compensation and statutory fees, or a fixed compensation and a portion of statutory fees. In the event that the collector of taxes is paid a compensation in lieu of statutory fees or a percentage of statutory fees, all remaining statutory fees shall be paid to the town treasurer at least monthly, or as directed by the selectmen, for the use of the town. Whenever the selectmen appoint the collector, such appointment shall be made prior to April 1 and they shall make a written contract with him in relation to to his compensation.