What is the ruling on turning over one's hands during supplication (Du'a)?

It is recommended to raise the hands in supplication while facing the Qibla, with the palms open and joined, and their insides facing the sky. Some scholars have held that when supplicating for the removal of affliction, the backs of the hands should face the sky, while for requesting something, the insides of the palms should be used. There is another view which maintains that all supplications should be made with the insides of the palms, and that what was narrated about turning the hands over during the prayer for rain (Istisqa') is interpreted as an indication of intense raising, a view favored by Shaykh al-Islam Ibn Taymiyyah.