Hi Thomas, 

You can find some useful information when selecting the soil type from this article:https://www.rhs.org.uk/advice/profile?pid=179 

The slope does not need to be particularly accurate bacause the slope mainly affects the maximum watering time. The larger the slope, the shorter the watering time, and itNetro will break watering into several times. 

Dry spots is determined by the springler system. If there are many dry spots, you can choose the frequent watering mode through settings->zones->specific zone number->smart zone-enabled->Mode. 

Thanks, 

Netro Support