Each servo comes with 4 or 5 different arms so you can choose whatever throw you need. With the new pooter radios, you can dial in what end point you may need up to about 125%.

To find center, remove servo arm and turn on radio and have that channels trim and stick centered, then replace arm as close to 90 deg. to servo.
I guess 160 deg. is close -- never paid much attention.
For aileron/flaps -- on 40/60 size planes use 2-56 rod. for 120 to 33% use 4-40 rod.