All claims and statutory allowances against an estate shall be paid by the personal representative, as far as he has assets, in the order specified in section 473.397; and no claim or statutory allowance of one class shall be paid until all previous classes are satisfied or it appears that there are sufficient assets to satisfy all previous classes. If there are not sufficient assets to pay the whole of any one class, claims shall be paid in proportion to their amounts. Exempt property, family allowance and homestead allowance have priority for payment, in the order listed, among themselves.