To set the default attributes for the warning zones:

ch.Set 'ZAttr' 'Green,10%,0'
ch.Set 'ZA' 3 2 0

You can use numbers strictly in the sequence shown above (Colour, Pattern, Weight). The patterns number from 1–15 and you can give an exact line weight in points for the edge. The default is Red, solid fill, with no edge.

See also ...
Colour Cycle
Nib Weights
Shading Patterns