[][]I'm setting up my Modeltech Magic but am not familiar with the term negative stick exponential. What is this all about and how would I set this up on my futaba 9caf

Negative exponential makes the stick less sensitive around center, but still allows full deflection of the control surface when you apply full stick. If you go into the D/R,Expo menu, you'll see how the curve affects stick movement vs. servo movement.