Wanda seems to be strongly dominate over Sizemore. Wanda is superficially respectful toward Sizemore but tends to be inconsiderate and curt. They have a functional working relationship but do not appear to be social. In particular, Sizemore's willingness to study fields of magic he has no ability at puzzles the multitalented but specialized Wanda to no end.
Wanda may have gained a greater appreciation of Sizemore as a result of linking with him to uncroak the Volcano. If Wanda believes that Fate requires that other members of her side attune to the other Arkentools, she may see Sizemore as a likely candidate for this role.