Hello
Could anyone help me out? I am trying to figure out how I can get this "Flip Offset"  property to pop up in my equations tab. 
I'm making a model that will have 20-30 reference planes like this and would be much more convenient if the angle and offset could be driven by equations. Could always just do 11/349deg as the angles but with so many planes that is going to become a mess real fast.

Thanks