Come to the Dark Side. "Smooth and Creamy" is for $5.00 cups of coffee.
However, I hear the Eminence Swamp Thang and Texas Heat have relaxed highs.
But, the correct speaker for a Mark III is the EVM 12L. You can find them on this board, eBay, used, for $200 or less. Huge bottom, accurate reproduction, nearly impossible to break.
(Last I looked, Jim Ansell had four of the EVs for sale, right here).