Thing is...you don't need super-advanced characters on the sphere grid; it helps a hell of a lot, but you can beat Evrae by putting as many folks in haste as possible, tons of Al Bhed potions, and Rikku in overdrive wouldn't hurt one bit. A level 2 k.s. and a level 4 k.s. can do about 9999. If she's not in overdrive and you have gil to blow, spare change is also very handy.
Also, staying close or far away is up to you.
I have a much better (and quicker) time with Evrae when I stay up close and only pull back when poison breath comes. Move back in immediately though.