Spoiler-I set low rate rudder to be just enough to hold knife edge and do that maneuver and four- and eight-point rolls at full throttle. You may notice that left and right knife edge require slightly different amounts of rudder and ail and ele coupling because of P-factor/torque. If you can't hold the nose up with a little rudder move the CG back; check by needing only a small amount of down to hold inverted. Jim