You guys are doing a nice job of hitting all of the important stuff here. The protractors and the long stick trick are key to getting it perfect.
Its really not that critical EXACTLY where the servo arms are as long as they are as close to center as you can get them and in the same place relative to one another. We typically shoot for as close to 90 to the servo case and it works out very well and keeps things simple.

The more important thing as Bill said is that both sides are in exactly the same place. Since the arms are essentially 180 degrees opposite of each other this can be tough since you are going to be 1 spline off all things being equal using normal servo arms. 1 thing I have found that helps is to use a double arm on one of the elevator halves and just flip it both ways and see which one is the closest. Once I find the best fit, I just grind off the other side of the arm to make it a single arm. Often one side will be a perfect opposite to the other srevo's arm.

Other things to check that wil drive you nuts are 1, the location of the control horns on the elevator. Stating the obvious, they need to be in exactly the same place on the elevator half, if they are even a little off it can be almost impossible to get them to match up just right. 2. Also measure and make sure that the servo "box" in the stabs were put in the exact same place. If they are off, go back to beating your head on the wall.

Just a comment
Now this is not advertisment just a fact I thought worthy of mentioning. The Hitec programmables make this a non issue. You simply put the servo arms as close as they will get, use the protractor and the programmer to put the centers at 90 degrees to the servo (or wherever you want them, point is they are EXACTLY the same). Then using the protactors as a reference to make both sides equal, you adjust the servo travel to get the desired endpoint and throw you want. You pretty much can set one servo up and get it right and then just go to the other side and program in the same servo travel on the other servo. Then there is nothing left to do but adjust the pushrod length to get the actual throws identical (takes about 2 minutes) and they will be PERFECT in every way. Then you simply go to your dual, triple rates and dial them down, everything is perfect.
It takes a couple of trys to figure it out, but once you do, any airplane you do wont take more than about 10-15 minutes to get setup on elevators. Ailerons are even easier because the servos are moving the same way. This is really the way to go now that they have worked the bugs out of the programmer. Just something for folks to consider in the future.

Here are a few videos on how it works if you guys want to check it out. This is good stuff for not only programming but just a good video how-to in general.
[link=http://www.downonthedeck.com/videos_instruction.htm]Servo Setup videos[/link]