I prune my China doll in Spring. New growth at the node nearest the cut off part occurs first, spritzing the stems after watering the soil helps. I guess it is too dry here, so it loves any additional moisture it can get, so after spritzing the bare stem I do notice new leaf growth on the bare nodes of the stem later when conditions are warmer. Before it just goes too bare on the lower part, and all new leaf growth is concentrated at the top end. My China doll tends to really grow tall, seeking the sun, since it gets way too shaded in its current location.
If you want since you got 12 stems, try it out with 2 or 3 stems, so you can observe and understand how the plant reacts to your pruning. But do it in Spring.
