I know you're kidding, so apologies for using this post as a springboard: Whether we declare war immediately, declare war after a (likely dubious on both sides) investigation, or delay war for later; the Entente will always, eventually, intervene with an ultimatum if they see we achieve too much success against the League. Therefore, we could at most pry Poland, Bohemia, & Austria proper. Probably Denmark too. Mayyybe Croatia-Slavonia if we're really lucky in the war effort. But likely no further.