It was still a good shave -- just not great.
What I make of this outcome is that the L.6, having a larger blade-bar span, allows more contact between the blade edge and the skin surface, which likely riles the skin to a slightly greater degree. The slight irritation caused me to not work as diligently on the final pass with the Weishi 9306-F, thus reducing the closeness of the shave.
Tomorrow I will use the same blade, the seventh use of the Bluebird, in my c.1948 Gillette Tech. The plan is to make a single pass, but this time that pass will be cross grain.
The focus of this plan is optimize the standard shave, which is a single-pass shave. The key to tomorrow's approach is using a medium-mild razor with roughly cross-grain, oblique strokes.
More to come. Stay tuned.