The paint I bought from Jim Carter sat unopened for about 4 years till I started painting. Then it was another year or so when I finished up. The tech sheet said 1 year, but I didn't have any real issues. I may have used a little more reducer at the end, but everything turned out OK. I used a gallon and a quart, and I think a quart might be enough for the cab. 4 quarts will cost you significantly more than a single gallon, but if bought at the same time, would probably be fine color match wise and extend your shelf life.
