Widebody Order Gaps

A lot has been written in the past about the orders that Airbus and Boeing need for the A330ceo and the B777 (non-X) to fill the production lines until the A330neo and the B777X will take over full production.
I started to collect the backlogs for both aircraft every month to see how the backlog will change over time. With the current or announced future production rates I can then calculate how many orders both aircraft will need.
Of course there are some open questions that will influence the number orders needed to fill the so-called gap:

• How will production rates change until the new aircraft will enter service