Description
Place the blueprints for [item=coal,quality=legendary] and [item=iron-plate,quality=legendary] which use [item=quality-module-2,quality=rare]. You can place more than one of each. Prioritize the iron plates coming from the coal setups. Each pair makes ~1.6/m [item=quality-module-2,quality=legendary].
Use the slow [item=quality-module-2,quality=legendary] setup if you only used one each of the above. If you used more, use the fast setup.