You can definitely cycle the slide with a 147 moving less than 1090, in fact it's probably pretty hard to safely get a 147 moving 1090. Your minimum velocity will depend on your recoil spring weight, how worn the spring is, what powder you're using, how firmly you grip the gun and probably a lot more. The only way to get an exact number is trial and error. My G17 will cycle 147s with Titegroup at just above starting data, I don't remember what velocity that is.