I just took both the 36R and regular Junior 36 for test spins and I have to say the 36R you are gambling with. I nice machine but not over the Junior 36. Your giving up a two piston motor for a single piston, hose real, fert. trays, smaller casters and wheals.
The 36R just appealed to me for a hitch mounted rack. But I think with a double hitch and third welded arm to truck frame you are probably ok with the regular 36. Or just keep it on a trailer.