Penangtan,
I grow Cephalotus at my balcony in temperatures from 25C to 35C year round. They are exposed to direct sunlight for a couple of hours during the hot season from June to September. The largest pitcher I have got so far is 2" but it is during recently when the humidity is higher and the air is cooler.
Higher temperatures seem to encourage more basal growth so the plant ends up with many more small pitchers then a few large pitchers.
Overhead watering is preferred in our lowland conditions. The species dislike their pots i.e. root portion getting heated up. I don't have a problem with that because the pot is shaded by my balcony wall.
The plants in the wild love full sunlight. However, because the weather is cool this season, the plants produced very large pitchers. During summer when the temperatures go up to around 40C, the plants lose nearly their leaves and pitchers. New growth is regenerated from the rhizome when autumn comes.
During the hottest time when my balcony got up to 35C, the plants did not show any sign of dying back. In fact, the mature pitchers produced were about 1.5".
Hope this helps.
