So a few days ago, I set up something to get some data on the melt zone extenders. The thermistor taped to the nozzle is the same as the one in the CHC pro. The AIO II is used here to get readings along with a fanless 24V 200W PSU. There is also a fan offscreen gently blowing air over the hotend.

The nozzle thermistor doesn't have desirable contact with the nozzle to get an accurate reading.

The CHC took 70s to go from 26C to 236C, and the nozzle took another 40 seconds to equalise at 153C.

Then I tried without the melt extenders:

There was a much larger temperature lag and eventual difference, only reaching 103C.

Next was a regular volcano nozzle:

Temp detected at nozzle: 170C

This is why I believe that the thermistor doesn't have a good amount of thermal coupling with the nozzle. Some kind of TIM would likely be needed to get an accurate temperature reading.

Lastly, I tested out the supervolcano with 3 9mm extenders (Ideally, I'd just use 1 30mm extender but I'd need to get a suitable M6 tap)

Temp detected at nozzle: 123C

TriangleLab's copper melt zone extenders may work better for this application. Regardless, next I will be testing out the flow rates in a future Project Log.