Parvritta trikonasana is insofar rather challenging as the hips are supposed to remain parallel and this is so difficult to control by oneself. It is easier to keep the hips parallel when going down with spread arms. When down the twist can be done. I learned this during the yoga fair last weekend and I think it is helpful. Test it yourself!
Hahahahaha, I did spell checking and it was recommended to write Pavarotti instead of Parvritta. For me this is now the Pavarotti trikonasana. The name of this asana is easy to remember now, isn't it.