So I'm having a custom cross frame built so I can try out racing (it will become a light around town trail bike and bad weather road bike if I don't like racing)

Given my (lack of) height I (and my fitter) suspect the builder will come back with a first preference of 650's. My preference is 700's since that's what my road bikes are and I have a suitable set of wheels already.

So ladies that have some experience in this 'cross area, what say you? How big of an issue would racing 650's be? (I'll never be "good" so these will be lower levels, local races). Can I find GOOD tires in this size or am I stuck with one or two mediocre choices?

Trying to make an informed decision on what set of compromises I'll be most happy with.

Thanks!