I used a Griffin copper/brass "29 A" radiator on my last project with a stainless mounting kit. The radiator sits on a thin piece of rubber on the frame rails at each side. A stainless bolt is inserted through the rail from the bottom up through the rubber and the metal mounting tab on the side of the radiator. A stainless spring (which looks like it should maybe be a valve spring for a Briggs & Stratton) is placed on the top of the metal mounting tab and a stainless nylok nut is threaded onto the bolt. The idea is that the spring is pushing down on the radiator and holding it to the frame, but the radiator is able to lift slightly against the spring on each side to allow some flex in the system. The locating rod bracket is soldered to the top tank like you indicated. The shell is then bolted to the radiator itself with 4 bolts and nuts inserted through the shell on the side and into brackets which are located on the side of the radiator. I got all the stainless pieces to do this here....
http://www.arizonastreetrods.com/