Look at the picture below....my 80" span camera airplane (carries a 35mm still camera) and is powered with a OS-90 four stroke and as you can see it has no rudder. My A-20 twin engine profile scale has ZERO rudder offset.

The line guide location and wing tip weight have the most effect, especially the adjustable line guide

Just put the rudder straight with no offset and get the line guide and wing tip weight right and you will be just fine.

The aerial picture was taken in flight at the Sepuldeva Basin flying site in Van Nuys, California. You can see the model airplane shadow and other models on the flying circle.

Fred Cronenwett