In trying to get an idea of what to use, what would y'all suggest for a great digital servo for pull pull on rudder for 1/4 scale 28 cc gas, and 91 FS F3A 66" wing span pattern planes. Thanks in advance for your suggestions.

As long as you stick with Futaba, Hitec or JR, you'll be fine. Shop for a metal gear 100oz/in (or more) with less than .2 sec/60 deg at the voltage you're going to run. One thing to keep in mind is the mechanical set up. Servo torque specs are rated at 1" from the center of the output shaft. Rudder pull/pull set ups can have 3" long arms or so which significantly reduced the torque applied, so keep that in the back of your mind.

Thanks Jeff. You basically confirmed what I was thinking.
Terry