I would not advocate not providing the standard three-point fitting of the rad, as it weighs quite a bit (especially when filled with water)to hang on just two fixing points. Bear this in mind given the vibration and shock-loads involved in the light of brass having a tendency to age-harden and ultimately crack.
In point of fact, I’m not too endeared with the three-point system as it is anyway – and on my Scott I’ve brazed threated bosses to the frame and threaded the through-studs to form solid right-angled fixings for the rad to positively locate on, which eliminates the rhomboidal stresses of the rad hanging on to studs which otherwise droop down at an indescriminate angle.
Give it some thought.
Don’t forget to earth the rad to the frame to reduce furring up!!