He does not seem to say anything around your lines. He does note the importance of using a fillet, and the major point seems to be that the fillet must be designed appropriately, ie. to preserve the original lift distribution of the continous wing. This seems to be straighforward, since drastic changes of lift distrubtion would likely cause turbulance. From that it also follows that the proper fillet design is unique for each wing's lift distrubution, which could vary greaty between design and design. Just like elliptical wing shape was not a "best" solution, neither the shape of the spitfire wing fillet would work for a Mustang, Fw 190 or Me 109 which had different lift distribution characteristics.
Essentially you thrown around his name and the people he lists as references without him actually saying something along your lines of Spitfire hyping...