Don't forget about the pictures. I dean it with this post.
I hope if they do an iPad app that it supports split screen because typing this type of reply becomes easier but here goes. In short. Ppl will correct where I have gone wrong as this is just my hobby not a profession.
Soil type; allows rachio to compute how long to water in a smart cycle before water starts running off.
Slope; is used in combination with soil type to determine max runtime in chunks before water runs off.
Root depth; how deep your roots grow. This allow rachio to compute how much water to apply (runtime)in a flex schedule to reach the bottom of the root without over watering. This is combine with soil type to break up watering in a smart cycle. So in short, if it takes 30 minutes to water to the root trough, soil type indicates how long they can water before taking a break for the applied water to soak into the soil deep enough to apply more.
Exposure: used by the flex schedule to estimate the amount of transevap that occurs based on the weather data they digest. They might also use it to determine how much water Evaps during a mid day run but I have seen no indication of that.
Nozzle: allows rachio to determine how much water is being applied per minute.n this is used to determine how long to run a zone to satisfy a deep watering to the trough of the root zone. This is also used in conjunction with area of a zone to estimate your water usage.
Efficiency: you research the difference formulas for determining this but describes how evenly your irrigation system distributes water. So in short, think of a bunch of rotors covering a square, there is a bunch of overlap, but not at the extremities of the square so these extremities do not receive as much water as the interior. Thus to reach full cover you have to over saturate the interior to reach the root depth of the exteriors. To what degree they use this information I'm not sure.
Allowed depletion is best understood by reading the flex document at support.rachio.com but I'll take a shot at a quickly here. This defines how much water you will allow the plant to transpire before applying more water. So think of a gas tank, this roughly defines how,much of the tank to use up before stopping at a gas station to refill. Does this mean that you should run to empty? No way, there are far too many variables that makes this a bad decision. For your turf you might be able to push that to 75-80, I don't know. I have it at 50% for all my zones except my tiff 419 zones, I take those to 80 but that is in part due to Bermudas very low permanent wilt point.
And this brings me to my last option, available water. You will have to read up on this because it is a scientific attempt at explaining a critical threshold for plants. In short it helps rachio determine the permanent wilt point for the plants being watered. The permanent wilt point is the point at which a plant can not longer utilize the water as the bottom of the root zone. Many many things effect this like vascular system, p.h., exposure, metabolic rate, on and on. So I think rachio uses this to determine if a flex should run even if depletion is within range. Because if the plant does hit the pwp, it's dead. This is at least the behavior I have observed on my annual bed zone.
I hope this helps.