I looked at that copper/brass radiator for the BB enjun.
Thought that was mighty impressive and would sure be a good edition,
the extra radiator cap would be an added bonus.
I also think that the brass and copper might provide better cooling capacity, but, I know I might be wrong on that too.
I’m not sure about the other two plugged ports, if they would be in a proper location for the by pass hose and the other one for the heater hose might be too small for these Montana winters.
Larger nipple could be added by unsoldering the installed port and soldering in a fitting that the proper size barb tite could be screwed into.