We've just aquired a 24 S250e system

We have the 3 marker optiwand. With the wand came a note stating that for wanding we should set the size to 500mm instead of the default 400mm.
The wand is a 500mm wand so this makes sense
The problem:
When i have the 'Wand Aquisition' > 'Wand Length' set to 500mm the cameras don't seem to pick up the wand properly, only very bitty green lines. When i set it to 400mm, it picks up the wand and the green lines seem more solid (Although not completley)
Could this be related to my other problem?
My other problem:
After calibration (400mm) I have to set the skeleton size to 5'
in order to fit the arena actor model properly even though my real actor is 6'.
Any help or suggestions would be very much appreciated.
Thanks!