I decided to go inboard with springs because it negates the need for the spring boxes . My rails were solid up towards the hump. I had a local shop bend up some 12g 3.5 tall with 1 inch flanges 4ft long and welded them into u shaped channels. Used some trimmings for end caps. The "resto" pieces are pricey. Pics on my build thread "disturbed duster" the metal shop charged me $30 for the steel and bending. Its pretty labor intensive so I couldnt really say what one would charge to do something like this .Look at the other rail closely, one is usually not far behind the other.
