Combos arent really viable on ifrit because of the short window you have to pull them off between each weaponskill, especially 3 hit ones. The only truely safe time to use them would be immediately following an eruption, any others if you don't have all 3 combos go off immediately there is a chance you will be hit by eruption, and even then, combos that end in things like simian thrash that take like 5 seconds for the animation to go off can't really be used because there isn't enough time between weaponskills.. Alternatively, if you try to time it across multiple weaponskills you risk losing the combo timer because if it uses either an eruption or a jump there is no way to keep the combo going. Because of this, I don't think many people have found a truely reliable way to kill ifrit. Everyone has to be on the top of their game and pretty much any death will result in a wipe because of the lack of chainspell.