[O] default list labelling?

[Paul Rudin]

By default when you demote a list item it's label is of the same kind as
the parent list. e.g. you'll get

1.
2.
   1. 

In practice I typically want to get a different kind of label: I'll want e.g.

1. 
2. 
   a.   

Is there a way of configuring what the sub-list labels will be according
to what the current one is?

On a related note it's normal (I suppose) to want consistency. So if we
have the following then it's probable that the first label under 2)
should be a). Is there a way of achieving this?

1)      
   a) 
   b)
2)