Packing, or preparing to pack

The bike is ready to roll, now comes the time to put all the bags on it and complete the puzzle that is planning a bike trip.
I will be riding with 2 rear panniers, 2 front panniers and a bar bag - all Ortlieb and all gaping at me like young birds waiting to be fed.
I have read that the weight balance between front and rear racks should ideally be split 40/60, and that each side of the bike should weigh the same in order to keep the bike stable.

With 1 month to go, I need to start getting my gear lined up, weed out the unrequired items of clothing, and get a basic idea of what I am going to be carrying.