Hello.

I use the JR DS3301 on rudder as well.

I got it from Al's Hobbies. http://www.alshobbiesstore.com/acata...gregor_93.html

Graupner has the same servo. It's called DS3328. I've used them for years with great succes.
http://shop.graupner.de/webuerp/servlet/AI?ARTN=5157

Torque is 4 kg, holding power is 9 kg.