I've never had a problem with stall turns, and I use Bryan's setups exclusively. I do use a rate switch for the rudder, though, because the snaps are way too fast with the rudder deflection I use in stall turns. As far as the tuck on left rudder KE, I don't know if Bryan has gone as far as figuring out why it is more prounounced than the right. Bryan states in his article that he doesn't claim to be an aerodynamic guru, he leaves that to Nat Penton. What Bryan has done is come up with a method of trimming to deal with the problems, knowing what causes them is not important. You may want to pose that question in the aerodynamics forum and see if they can come up with a consensus answer (they probably won't).

Edit: BTW, Bryan is in the final stages of finishing his latest project. I'm not sure if he has time at the moment to check the forums. I can't wait till he finishes this project either. This one is gonna turn some heads!