Ray-
The magazine article you referenced was authored by the designer , Art Schroeder - and the plans therein reflected his thinking at that moment in development of the Eyeball.
It should be noted, as you point out , that the ORIGINAL design DID NOT come into being utilizing a built up wing.
Despite comments to the contrary - I have J&J's drawings for the kitted version--------IT WAS A FOAM CORED WING----- as per Schroeder's published version.
The 'stretched' version of this design was the result of Schroeder's effort to gain a more stable platform (in pitch)and WAS constructed around a built up wing in conjunction with an additional 2.5" in the fuselage.
Eureka's version represents the final iteration of this design --with built up wing.