I'm not all that familiar with the inner workings of the firmware, but I'm sure there is a change temperature command that doesn't require the toolhead to be switched.
If there is another change temperature command that you want to use, just go to Tools > Firmware Configuration, and you can enter it there.
Re: multi process tip - gcode
In my last post I was considering trying changing the hotbed toolhead for that process to T1. Wouldn't change the m-code but it would change the parameter. I think the parameter is ignored for the hotbed temperature change but have to try it and make sure that would work.
