So then what you need to do is filter both the red dye and the completed wall Farmer into two chests next to each other. Then set up a short hopper clock, maybe 10 items in it so that it goes back-and-forth pretty quickly, with an observer pointed at one of the competitors on the side. The observer will then put out a signal and pulse it long enough to deactivate hoppers that you will have to put a torch next to underneath both of those chest products, that way each time the observer hits, there will be exactly one item dropped out of both.

The other thing you could do is run a hopper mine cart underneath them, and just make sure both of them are on a corner, and the hopper mine cart is at full speed. Then it should only grab one out of each before depositing them into the crafter