What's the general consensus on priority for a Frost DK these days?


At the start of the fight, each DK has 2 death runes, 2 frost runes, and 2 unholy runes.

Should the priority be aimed to get 4 necrotic strikes and 2 howling blasts? Or the other way around, with 2 necrotic strikes and 4 howling blasts? Or 3 of each?