[Chris38]

Spoiler for 43:

Speaking about the training arc, I don't think that it could be even dragged further. Of course, it could be possible, for Ikeda to specify what kind of techniques, but doing something like that wouldn't make the raid omn Fairy Tale's HQ as suspenseful as it currently is, when we don't have a clue on how powerful Tsukune has became, during his one month training with Tohou Fuhai.

Anyway, from the looks of it, youjutsu techniques are separated from Tsukune's Shinso vampire powers, since Tsukune's appearance hadn't changed when he used them - you now the red hair, vampire eyes form that Tsukune enters when he uses his vampire powers.

Of course, another possible explanation is that so far, Tsukune used pretty low level youjutsu techniques, that don't need a lot of Tsukune's youkai energy. On a different mater, I think that, the first serious opponent that Tsukune is going to face, will be Miyabi, giving us the rematch between him and Tsukune, that was mentioned in the Yuki Onna arc.