Agreeing with Cherub Agent, most Water-types invest heavily in physical defense so a special Grass-type move is better (frankly I'd use Giga Drain since it's a means of recovery and Grass Knot isn't that much powerful against its targets anyway, except for the incredibly heavy Suicune lol). Also, I used Earthquake to have it act as a secondary check to Raikou w/o Aura Sphere (mainly SubCM), it needs 283 Attack EVs to KO it after SR and one turn of Hail in case you're planning on giving it a more special bias.
You say 112 EVs helps outspeed Blastoise, which is wrong. 112 reaches 184, while minimum Speed Blastoise has 192 Speed. Getting min Speed Blastoise seems like a big deal to me.
In a similar topic, I don't like the EVs of the SubSeed set. It can't set up on much, which is why I'd strongly suggest you invest heavily in Speed, to at least get min Speed Blastoise again (148 EVs are needed) so as to prevent it from Toxicing you. Actually, that benchmark should be for all sets except for Scarf imo. What I'd do is max HP, put enough Speed for Blastoise and the rest in Special Attack, but that's up discussion.
I also find the lack of a Choice Scarf set disturbing, I haven't actually tried it but it could be useful even in UU where there aren't weather wars, so I wouldn't dismiss it so quickly. It also has a good surprise effect against stuff that think can KO you, such as LO Nidoking—it can also beat Tornadus iirc.