Are you just using the sour dough starter and nothing else for the bread to rise?? if so I would use about 2/3 cup if you are using the starter along with yeast then 1/2 c. If only using starter it takes a lot long to rise about 3-4 hours.
What you do the night before is take the starter out of the fridg and add 1/2 c flour and 1/2 c warm water let it set on the counter over night then use it the next day. You don't have to add anything after you use it unless you want to. other wse just put it back in the fridge until you are ready to use it again
I hope I am not confusing you.