Excellent post, thank you.
A DC3 in Aus many years ago had carb icing in cruise on a nasty night. The crew applied full carb heat, disregarding the Carb Temp indicator. They continued on, with the engines both detonating badly due to the intake temperature (well over 40 degrees C) until both engines failed and they crashed, killing all on board.
Many years later, also in a DC3 I was flying over the Simpson desert on a search with an OAT of 45C. Both engines backfiring every 30 minutes or so. What I needed there was carburetor cooling!