Not sure how you flew formation Ken, but in all the large aircraft formations I've flown I haven't needed to look up 30 degrees whilst I'm in formation. If I did I would have been well out of position. This is close formation we are talking about.
When you are in a 30 degree bank, the horizon is 30 degrees "up" in your cockpit. If the aircraft you are formating on is next to you (i.e. on the horizon at your 9 to 10 o'clock) you cannot see him. Or are you saying you always made flat turns while in formation? Or made no turns at all?