Well your question doesn't seem to make sense, you are asking about how to keep your hands "far away from your head" but then talk about shoulder turn flexibility.
Anyway, to help with part 1:
Feel like you are using your right hand to push your left arm away from you. Here's a drill:'
Make a fist in your left hand and put up your thumb like you're giving the "Thumbs up." Then keep your hand in that position and then pretend your left arm is COMPLETELY DEAD, LIFELESS.
Now using your right hand, grab the left thumb and push/pull your left arm straight while making a shoulder turn. This will keep your hands far enough away.
In essence, this is "extensor action."