Most people today would say to forget about rudder offset. I have broken arf rudders that come with offset just to set them straight.
The offset works best when you don't need it--at level flying speeds where the air flow over the rudder is the highest. You just want to make sure it isn't bent the wrong way.

hey Joe . Just got back from delta park, with my score  NO OFFSET is needed. somewhere in that plane they havemore pull than is needed.i even adjusted  leadouts forward to give my arm some relief. mine is K&B 61 power on 65 ft lines.GEOFFREY drying after  a damp day at the site.