For all you paint experts out there. Getting ready to paint the interior of my new shop. Plywood on the walls, so I'm using Sherwin Williams Extreme Block stain blocking oil based primer for the first coat (which is on sale for $25 a gal until Monday). Planning on doing two coats of latex over this, some shade of off-white. Trying to decide between Sherwin Williams Superpaint versus Duration. The Duration is on sale through Monday for $41 a gallon, while I can get the Superpaint for $30 a gallon. Sherwin Williams guy is trying to sell me on the Duration being worth the additional $11 a gallon. My shop floor is 3100 sq. ft, but I have approx. 4000 sq ft of wall to paint. Worth the extra money for the Duration paint?

