Awe, come on! That is where all the fun is at!!! 
I haven’t had a chance to mess with some of the new ML settings yet, but I’m far from a “super geek gardener” and I was able to follow the steps to find my soil type, root depth is pretty broad (shrubs could be anywhere from 12-18", established tree could be 20-36"), and really the other useful bit of information is the precipitation rate of your drip emitter or sprinkler nozzles. With that information, you are doing pretty good dialing in Rachio.