Jump ball & movement?

[fan]

I know that when the referee is ready and until the ball is tossed nonjumpers shall not move onto the circle or change positions around the circle. When is the referee ready? Is it when he enters the circle for the toss or just before he tosses it? I've also have heard nonjumpers cannot move until the ball is tossed. How strict are officials with this? Would simply bending over cause a violation or moving your arms? What type of movement by a nonjumper would get a violation (I already know moving into occupied space or having a foot break the circle plane would)?