bgi,
I 'll try to address your concerns with what I have learned doing my setup.

1. Mis-alignment - The socket and shaft for the two outer arms are square. You can orientate them at any of the 90 degree positions relative to the center arm. With them being square I don't see how they can mis-align unless one is defective. You may want to swap your Bell Crank for a replacement. You will notice some loose play in the opposite arms until you tighten the long screw that holds them together. If the center arm being down does not interfere with your Rudder cables, then go for it.

2. Holes and Clevis. At the Bell crank end I used 4-40 rods with Z bend. I drilled the holes out just enough for a VERY snug fit on the rod. ZERO play, and one less piece of hardware to adjust.

3. Over-throw. - With the short standard arms you have to move the end point further to get sufficient elevator movement. That is why I extended the arms. I used a heavy duty Dubro arm on the servo. I also used a heavy duty Dubro control horn on the elevator with clevis in the bottom hole. I cut the rest of the horn off. Look very closely at the end point travel marks in my picture referenced in the thread above. Arms only travel 30 degrees from center, do not even approach over-throw. With this setup my servo is set for 100% end point, and I still get 65 degrees elevator deflection. I use an HS 5945 servo at 133 oz torque which is more than enough.

Sorry to hear about the GMA field. I have never flown there, but have it on my list of places to visit. I hear there are some really good Aerobatic pilots there. I'll take all the advice and help I can get.

I plan to be at Perry also. Maybe we'll see each other.