(a) The share of a surviving spouse shall be:
(1) If there is no surviving issue, the entire statutory will estate; or
(2) If there is a surviving issue,
(i) subject to any lien or encumbrance, the testator's residence and tangible personal property, except personal property held primarily for investment or for a commercial, agricultural, or other business purpose;
(ii) the greater of three hundred thousand dollars, or one-half of the balance of the statutory will estate; and
(iii) subject to the provisions of subsection (b), an interest in the remaining portion of the statutory will estate, including any property that would pass under the provisions of subclauses (i) or (ii) of this subsection but disclaimed by the surviving spouse, in a trust upon the terms set forth in section six.
(b) If the personal representative, other than the surviving spouse, determines that the trust under section six would be uneconomical, the entire statutory will estate shall pass to the surviving spouse.