My thought on using a spot on the bike was that airflow over the bike would have it pretty much at ambient, given that the temperature was checked shortly after stopping. For example, it could be checked at a gas stop under the awning often found over fuel pumps. That's why I suggested the steering head, as being in the airflow but not in the heated airflow behind the engine. The master cylinder might be another suitable spot. As you say, a little experimenting is in order.