475 Gallade

Confusion is the preferred fast move for Gallade. 

Leaf Blade (2.0 DPE) is one of the best charge moves for PvP, and is almost essential for Gallade even if it lacks STAB. A very low 35 energy cost of means Gallade only needs 3 fast moves to be able to use it. Close Combat provides key coverage against Steel, and it's extremely powerful (100 damage for 45 Energy) but complicated to use, due to the big Defense debuff that it triggers at each use, especially damning on an already frail pokemon like Gallade.

Due to the poor energy generation and lack of STAB, Charm tends to perform worse than Confusion in most cases. However, Charm does give Gallade wins against some of its counterpicks, which may be preferable if you value a surprise factor.

Synchronoise is an exclusive move featured during Ralts Community Day. It costs a modest 50 energy, sports a respectable 1.60 Damage Per Energy (DPE), and gets STAB on top. However, it is typically not recommended due to redundancies with Confusion, sacrificing valuable coverage that would be more preferable for Gallade's role. It also doesn't synergize well Charm due to poor energy generation. 

Gallade is a rather fragile Pokemon, with a stat distribution aimed for offense that results in poor bulk in comparison to its competitors. A rather unusual moveset makes Gallade more of a niche pick depending on the situation, as its primary offensive threats in the form of Confusion and Leaf Blade are not typical. Though that can potentially work well with Gallade's high ATK stat, just keep in mind that with a low bulk he'll likely need to be shielded. The addition of Charm gives Gallade even more plays in niche situations, as Charm can beat Dark and Dragon-type counterpicks such as Sableye and Altaria, at the cost of losses against Pokemon it would otherwise win against. 

Wins against Fighting- and Steel-types escorting Giratina are to be expected, while Leaf Blade ensures victory almost any Water-type that's seen in this meta. Unfortunately access to Charm is not enough to deal with either Giratina, which puts Gallade in an awkward spot since it loses to the bulky Psychic-types who already defeat the Fighters.

Gallade doesn't have the legendary stats needed to compete at the top ranks, though its high offensive stats and moveset combo still net some wins against Pokemon weak to it. Positive matchups against Lucario, Tyranitar, Swampert, and Melmetal are nice, but losing to most of the big legendaries ain't so hot. Relying on Charm to deal with prevalent Dragon-types in this league is also not advisable, as a narrow win against legacy Dragonite doesn't make up for losses Giratina and Dialga.