ORIGINAL: white pulsss
Are the measurements from center to one side or from one side to the other. Eg. should the rudder move 20mm from center stick to one side, then another 20mm from the center to the other side giving me a total of 40mm movement?
Yes, just like you have described it: measure from center to each side.
Sorry, I don't know about your receiver, here is a review:
http://www.flyrc.com/articles/spektrum_dx7.shtml