The procedures are based on a minimum rate of turn. They expect that you will turn at a minimum rate of 3deg per second (rate 1) up to the point where this requires 25 degrees of bank (airspeed 180Kt aprox). At higher speeds, the turn is calculated based on a constant bank angle of 25 degrees which of course will give less than rate 1.
There is no specified maximum rate of turn that one can use just the same as there is no specified maximum rate of turn for visual turns onto final.
However since we teach VFR pilots not to tighten the turn onto final if they are going through the centerline (danger of low speed, high angle of attack, ball not in the middle, distraction, spin etc) it is entirely logical to teach that same safe practice when flying a turn on instruments especially considdering the posibilities of disorientation and the inherrent errors that can affect the gyro instruments after a steep turn.
Think back to your own IR training and how you positioned the aircraft in the hold or on the outbound leg.
Regards,
DFC