I haven't had much success with Solgaleo. I think it probably should go down to C+
Too many threats can come up it pretty easily, such as Giratina-O, Zygarde-C, Arceus-Water, Mega Sableye, Ho-Oh (Stone Edge could fix this, but it's very risky), Lunala, Palkia, Kyogre, and especially Primal...