There is no right answer bud...
Depends on your preferences, what your lungs can tolerate, the juice you happen to be using, your mood on that particular day, and whatever else.
I can tell you this: on my IPV3 Li, I'm somewhere around 30 Joules and 400F with a Herkales Ni200 0.2 ohm coil... Are you using Ni200 or Titanium coils? because you should be
But your device is different, and your preferences are different than mine. Heck, with my VTC mini, I'm usually at 30 watts and 450-480 degrees, so figure that one out!
Best of luck to you... it's all trial and error... it's hard to get a burnt hit from TC, so don't worry about playing around with it.