I don't follow post #112, how to have grounded cathode with CCS. Does he mean CCS drawing current from the cathode of each power tube and using bypass cap from each cathode to ground to give an AC ground? I don't see any difference from just simple grounding the cathode. Usually people adjust the bias current to adjust the wing spread AFTER optimize the design. Using tube to do CCS is too complicated. If I were to go with modern design like CCS, I would use BJT as CCS. BJT is perfect as the output impedance ( like rp in tubes) is way higher than any tubes can touch. ONLY reason to use CCS is to provide a very high impedance current source so the current source approach an idea current source. Using bypass cap just does not make sense to me. Unless one actually hook up the two PP power tubes as differential pair ( long tail pair ). I actually thought about that before also. Then it will make a whole world of sense to use CCS tail to make it ideal. But that only work for class A, not class AB.