Nice looking rig, solid & no skimping on the firebox. For your RF plate, I just had the metal shop cut me several 1/4"x6" plates. For RF, I put them in tight against the firebox opening and each other leaving about 6"-12" open at the end opposite the firebox. Or you can space them out a little and they will act more like a baffel plate. very versatile.
Got a bunch of cooking toys and a custom metal fabrication shop where I spend my time building all sorts of smokers & outdoor cooking gear.