Opening it to 2.5 turns gives a richer air/fuel mixture at idle speed, making it easier to start the engine. The 2.5 turns may need to be fine tuned. It may vary because of air tempurature, humidity, altitude, etc. Mine is set at 2.25 turns.
IMO, other than opening the pilot screw 2.5 turns, I would wait on any mods until after engine break in, 600-1000 miles.
Good idea to change the engine oil between 100-200 miles on a new engine.