First, a worst-case thermal test (leads shorted, amperage knob all the way up).
The hottest point I could find by probing with a type-k thermocouple was the head of the screw which secured the pass transistor to the heat sink.
Ambient temp at the time of test was 23C.
At the 5-minute mark, the pass transistor screw measured 72C.
At the 10-minute mark, the pass transistor screw had climbed to 82C.
I also measured the bridge rectifier (four discrete 3 amp diodes), which read quite a bit hotter at 93C (this surprised me a bit).
There was another transistor (a TO-220 D880Y) which read 68C.
I also measured the transformer case, but it was only 33C. After powering it down I felt the transformer to confirm, and it seemed very mildly warm.