TigerMom, this is a situation where a sizer cycle would be really helpful. A fitter could mock up the tow different bikes based on the gemetry given on the website and you could sit on both just to see how they feel fit-wise and then make your decision based on fit and projected performance.

This is exactly the kind of service I was hoping to provide with the purchase of a sizer cycle. But I'm not there yet. You could see if someone in your area has a sizer cycle and might be able to do this for you , if you can't find a demo.

I spent some time last night looking up geometry on various 650b bikes and I was surprised to find that all of the ones I looked at had a higher standover than the two that you listed.

Have you considered steel? It's slightly heavier (by that I mean about 1 lb for a good steel frame) but it would open up your option significantly.