Yes, in this instance, "secondary rocker" refers to "spin rocker". Wilson is not cooking up this terminology. I've seen it elsewhere. From a grammatical consistency perspective, it makes sense when used in conjunction with primary: primary, secondary, tertiary, .... Note that the "primary rocker" is often also referred to as the "main rocker". "Secondary rocker" is a more generic classification than "spin rocker", since that portion of the blade is used for moves other than spinning.
Caveat: Some references refer to a "compound spin rocker"; i.e., a spin rocker with, e.g., two radii. They will then refer to a primary spin rocker and a secondary spin rocker.
It would be much clearer if Wilson followed Paramount's example, and gave the nominal target values of the radii for the spin rocker instead of the vague "aggressive", "subtle", and "standard". Even then, as Bill's measurements have shown, however, real-life profiles are more complex, and can't be characterized by one or two values. Especially taking into account manufacturing quality control and the vagaries of sharpening by techs.