Don't mind me sharing my thoughts, based on the same situation we were all in. Putting the technical part aside, the shots have to start way before any model comes walking down the runway.
That means.. U got to have some visual idea in your mind that you would like to make real! To me I love the flare effect on the hair, so i picked the spot which will directly face the spotlights.
At least 15 minutes before time, u have to assess the hall and see where the lights are, where's the end of the runway, where will the models start coming in, and stand where you think is the best spot. This itself helps alot in getting the shot you want.
For the kit lens, I think it's best to get directly on the right side of the stage on day 1, and left side of the stage on day 2. When you are this close to the runway, YOU DON"T NEED the CLEAR IMAGE ZOOM and can use F3.5 and a faster shutter which should help in your pics for that session.
And if it there's still some focus hunting.. bite the bullet and pick DMF or MF and trust the focus peaking of our NEX, turn off the review, use Cont.mode /speed priority. So far no other competitor has anything better than Sony's Focus peaking as what i know of. Good Luck!.
Thanks for the advise! I guess it's all about the strategy to overcome the limitation of the kit lens after all... like u said, should have go closer & rely on the focus peaking...