I talked on the phone with the guy at Streetmaster, he said due to the extra oil capacity (1 liter) gained by using your frame tubes, the cooling gained exceeded the stock radiator at all levels, including doing laps on the track. He doesn't sell the modified frame sections for our bikes (only Bonnies) but I looked at my frame and concluded, entirely doable, just need the weld on fittings and a certified weldor (like me) to apply the glue. I think one would want to do a serious flush before pumping oil through and into a motor. On the other hand, being that the Pacific Northwest seems to be exempt from "Global Warming", I'm considering a oil heater.
