The first thing to do, is to establish a plan. Depending on where you are, you may or may not have an easy time beating Yunalesca. For the most part, I will assume Auron can only do 1750 on average. If you have Holy already, then you need mental help. Seriously. Excessive level is for excessive idiots.
No, it's not. Excessive leveling is to get a lot more out of the game and make those really tough boss fights (Seymour Flux) easy.