Bill,

As weird as this is going to sound it works well. I'm sure someone else will have other ideas.

Take 2 pieces of nice straight balsa sticks and tape them to the top of each elevator so that they meet right behind the rudder. Now move the sticks on the transmitter and you will see if they are moving equally and at the same time

I suggested this over in the Wildhare forum and the guy went so far as to use spring type clothes pins and glued the sticks to them. Easy to do and will definitely show the problem. I have also since done the same thing (spring type clothes pins) and it really does work well.

EDITED for really bad wording on my part YUK [:'(]