Good news: I have no IHS so direct die measurement is theoretically feasible
Good news: I have a thermocouple and the bead looks like it should fit under the heatsink
Bad news: my Fluke 179's temperature calibration is ridiculously off (showing current ambient as 2.2C!!!)

I kind of tabled this project while I have been working on something else, but that has just about run its course. Can anyone suggest how I would go about getting my Fluke calibrated?