It's not official, 196 mods just mentioned blahaj zone in a sticky about Reddit alternatives before going dark. There probably won't be an"official" one coronated I wouldn't think.
They're both the same size (~350 subscribers). If you're viewing an external community on your home instance it always shows less users. (I think it's federated users shared maybe?)
Instance size doesn't really matter. If anything smaller can be better to avoid being on an overloaded instance.
That said I'm not really advocating one over the other. And with how Lemmy is set up it doesn't really matter to have some redundancy imo