Bread-Bakers v107.n012.2

I have made the no-knead bread several times & it has turned out 
perfectly each time.

I would like to make a sourdough variety but don't know how much of 
my sourdough starter to use?  Should I decrease any of the liquids 
used?  Is there a particular time when it should be added?  Finally 
is there any other suggestions to help me make this bread?

Thanks, Keva