I set mine between 200-210 C pending on how dry, finely broken up the material is, and how much you put in. Its equivalent to 392-410 F.

I usually fill the clear space halfway or lower, and can get a good 15-20mins constant vapor. The more you pack the more time you can get, up to an hour, but temps may need to increase to heat all the material to temp. When you start seeing less vapor, shake or stir the bowl, it'll come back once to four times at least.

Also, you may want to play with the temps for the baloons, I usually go higher for more 'smoke' look to the bags. Won't last as long though.

I've owned it since April and used it almost everyday. Its been well worth the price.