Do what you want but in my hands with a worked sb plus a Vortech supercharger, the DeWitts sb radiator with the recommended SPAL puller fan and pulse width modulator (that they no longer sell) my '65 will idle at drawbridge openings at 195* all day in 90* August heat. Except for August, the car invariably runs on the 180* tstat.
I happen to have the bb radiator you're talking about in my 66 bb car and IMHO, you're going into overkill. THAT car will sit at the drawbridge with the AC on and barely touch 190*.
I never viewed this hybrid mounting system but if it's Tom, it WILL fit and the horn relay wouldn't be my first worry. HOW MUCH horsepower you running there, big guy?