Will you be using a skydome to provide additional lighting to the scene.  As meatSim posted, BB's envsphere is an exceptional prop which can add considerable ambient lighting  when used with IDL.  Provided that you are using one of the most recent iterations of Poser.  I normally render such a scene with 1 infinite light set to white or slightly yellow at a low intensity depending on the image used on the dome.  Then again, daylight can be at any time of the day, morning, afternoon, and early evening.