Well, yeah, Jabra probably had the 2nd strongest tekkai of all CP9 at the time (he was the only one who could use tekkai kenpo too), so it was a fitting challenge for Sanji back then. Also, I agree that base Sanji would be able to defeat the weaker CP9's. Both Zoro and Sanji needed Asura/DJ to defeat their respective opponents, but due to different reasons: Zoro was able to break Kaku's tekkai, but he needed more "arms" to surpass Kaku's yontōryū style + DF; Sanji on the other hand could match Jabra's speed and most techniques, but had to use heat/fire to burn through his tekkai kenpo.
Anyway, I strongly believe that Zoro was using ryou for most of his fight against Kaku, and it's clearly alluded during his Shishi Sonson in chapter #416.