Help with my sourdough pre ferment

Very new to sourdough but loving a new sourdough pizza recipe I have found. It calls for 50g sourdough starter, 100g of water and 100 flour to be mixed and fermented overnight. This is than used to make a dough.  

my question is what state should be sourdough starter be in when it is added to my preferment? Hours sense feeding, just starting to fall etc. also is this really any different that a direct dough? 

Does the float test matter here? I’m thinking not. Also I’m guessing older sourdough starters like fed 24 hours ago will produce a more sour preferment, correct? 

I just made the preferment with pretty old starter, maybe 30 hours sense fed. Did not float. Hoping for a more acidic dough.

thanks for the help