The rudder issue is primarily one that deals with a very bad tuck to the gear when attempting to execute a knife edge. I emailed Bruce and asked about this and he informed me that the original 4 Star design had the horizontal stab located too high on the fuse which resulted in this tendancy. My question was how should I modify a 4 Star 60 to get it to fly a good knife edge like the BTE Venture 60, Bruce's reply was to move the stab about 3/4 of an inch down. Basically this puts it on the engine thrust line, built stock the stab is well above it.

Adding area to the rudder also helps in my experience if you like to do maneuvers like hammerheads or stall turns. One thing you should NOT do is take the dihederal out of the wing if you are attempting to improve the knife edge characteristics since the design needs some to reduce roll coupling tendancies.