I use one all the time for brewing sencha. While I've never measured the temperature coming out of that tap, I know that when I use the same tea at home (where I have a variable temp kettle) and at work, I 'can' get the same results. Here is what I do:
- pour water into my kyusu, rinse and empty in the sink
- pour water again into the kyusu (walk back to desk...people looking at cool kyusu have curious questions and then I try and convert them
- after 30s or so, empty kyusu into my cup, then back into kyusu, and then back into cup (this cools the water down to where I like it, you can experiment with what works for you)
- I add leaf and pour from the cup into the kyusu and time it
- for second infusion I add water to cup...wait a few minutes and then add to kyusu for second steeping (I don't time this, I'm not very picky)
- if I want a third steeping, I add water to my cup and wait a shorter time before pouring it into the kyusu (the sencha likes the hotter water for the third steeping IMO)
Other minor adjustment you can make is to vary how long you wait to pour the water from this tap based on where it was in the heating cycle...like if the 'heating' light comes on during or just after you use it, then it was a bit cooler than if you use it just after a heating cycle.
Good luck and enjoy!