It really depends on what characters and how easy it is for you to farm the dungeon(s).
Insanity isn't very difficult with newer, awakenable, characters. I've farmed it for a couple days and I've only got a couple thousand frags left. So it's doable with the right characters. I'll have BHE tonight. If you run insanity, the ironite return essentially makes up for the cost of a mega-refill, with about 20-30 short. So it's not as costly in terms of ironite as it may seem.