Distance and Direction Vector Accuracy

Are there any rule-of-thumb accuracy specifications we can use to plan our Nearby Interaction apps? For example, in ideal cases (phones are facing each other with clear line of sight), what sort of distance measurement accuracy can we expect?

What about the refresh rate for position updates? 10Hz?

Similarly, when conditions are less than ideal (for example, devices are not facing each other in the antennas beam pattern), does the distance accuracy degrade significantly? I know we'll lose the direction vector.

Thanks!