I am building the tool to do just about that exact same thing. 4" twin rows on 15" centers. 15" centers on the strips, with the tilled strip about 7-8" wide. Lots of nutrient forms and placement abilities. Most of the bolt on parts are from Roll A Cone. The tire on the back of the strip is for more dry conditions. Other tools can be bolted on for wetter conditions. Still need to put a device between the strips, roll a cone calls them "sliding fenders".