Hehe. It's possible that he has a dark factor as well, causing his grey to be darker than what you'd expect on a sf. Has he produced any cobalt blues or were they all sky blue?
He is quite the handsome man! I've always had a fondness for greys.
I wish I could get into breeding budgies, but currently I don't have the space or resources to do so.
So for now, it's just a future goal of mine.