Mary, we were taught to use a rather shallow climb attitude (30-45 degrees or so) for the first 50 meter because with a steep nose up attitude you will not be able to recover from a cable break fast enough. After 50 meter you can pull to a very steep nose up.
In reality it's a rather smoother process where initially you let the aircraft accellerate until 130 km/hr or so, and above 50 meter you smoothly pull a bit more, for a target speed of 100-110 km/hr.
Last instructor I had did not bother with it that safety altitude at all, as long as you did not climb too steep initially. He told me I must've been taught by an old school instructor.