Put the item you want in the bottom constant combinator on the left, destroy and replace the rightmost not equals combinator, and you're good to go! You just need to supply the plant on the left. The plant on the right will try to build whatever quality items it can in pairs of two to keep the productivity bonus.
Is this terribly designed? Probably. Do I know what half these combinators do now? No. Is this at all practical? No idea, but it's my first real circuit design and I'm proud of it.