Hmm... Castrum Abania is doable with i270, doing what previous people mentioned. Still, as a main tank, I think there's enough ways to have a better, decent ilvl at that point. I usually went with i270 until Bardam's Mettle, then gearing myself with that dungeon. The time it takes you to reach 67 you can already gear yourself to then go gear yourself with Doma Castle gear. It's a bit disrespectful to not be at a proper ilvl for that dungeon, since you make not only the healer do extra work, but everyone in the party (more MP/TP wasted between pulls, etc).