Went with regular cheap studs and extended the couch to make 4-across seating. Probably should have used better wood because it was hard to find studs that were straight and not full of burrs and knotholes! AND...studs are actually 1.5" x 3.5", so keep that in mind if you go that route when you're cutting from detailed plans because your dimensions will be off slightly. Staining and adding spar urethane coat took the longest amount of time. Cushions are 24" x 24" from Lowe's. Wood = $80, Cushions = $180. A little extra for screws and a few pieces of hardware. This pic shows the couch without a back brace that I added later. It's a beast, too! After all that wood the couch probabaly weighs close to 150 pounds!