It kinda doesn't matter? I would wager this will likely eclipse the fediverse's total userbase in a day or two. They simply post a banner for logged-in IG users, "Tap here to get the new twitter-murdering app, no signup needed", and they have an instant eight-figure userbase.
Yep. Assuming this [1] site's count of 10m fediverse's total users is accurate, Instagram would only need 2% of their ~500 DAU to sign up to surpass it; only 0.5% of their MAU.
