Before making an appointment under the provisions of this article the court shall be satisfied that the guardian whose appointment is sought is a fit and proper person to be appointed. Upon the appointment being made the guardian shall execute and file a bond to be approved by the court in an amount not less than the sum then due and estimated to become payable during the ensuing year. Such bond shall be in the form and be conditioned as required of a guardian appointed under the guardianship laws of this state. The court shall have power from time to time to require additional bond. No such bond tendered by a guardian or committee appointed under the provisions of this article shall be valid unless the surety thereon shall be a solvent surety or bonding company authorized to and legally doing business in this state. The premiums on such bond shall be properly payable out of the estate in the hands of such guardian or committee: Provided, however, That where the total estate coming into the hands of such guardian or committee shall at no time exceed the sum of $500, then a bond with at least three personal sureties thereon may be accepted if such personal sureties are solvent and are worth, respectively, the amount named as the penalty of the bond.