how to create an array with both members and number of members undefined

wildbill:
You only set servoTime in setup, when the values of the things you use to calculate it are all zero.

As to using a function for rewind and playback, I'd expect you to pass the delay to it as a parameter. InPos & outPos too of course.

Told you I was doing something stupid...
So I'll put the calculations into the loop. Thanks.
Not sure about you 2nd comment though. I do not need the rewind to move at the same timing as playback

EDIT: Did and it works. Simple and great.
Thanks a lot!