[Slash]

Good questions, but I don't know what the various heater specs are. As you've indicated, the Bosch website is nearly useless.

However, it seems to me that, since the function of the heater is to get the sensor up and running, if the sensor is functioning as soon as you say it is, it must have the right one! (Wow, am I supposed to have that many dependent clauses?)

I also found that the shield around the tip can be different between the various models. I don't know if that will make much difference either - especially since your application did not originally call for a heated sensor.