Almost jumped to 7NT after 4C. But I said wait a minute, who in tarnation knows what GIBBO is up to. Came out on the bright side this time.
Was fortunate it did not convert to 7C.
Well done, a result! But a human East would have bid 6♦ like a shot at this vulnerability. As for bidding 4♣ with the North hand vulnerable in 2nd, well it's aggressive at best, suicidal at worst.