I like the diagnostic thought involved with your technique.
If you can get access to an infra red thermometer, you don't even have to go to such extremes. Last week I drove an old (1977) 450SL around the block and put it directly onto my drive-on lift. The Front right disc was320 degrees. The rear right was 280 and the other two were about 150. We rebuilt all four calipers.
Bosch Master, ASE Master, L1
33 years MB technician