Here is a close-up view of how the stack is staggered, using the classic, a coin, as a scale reference. Two leaves is about the maximum that should be done at one time using this stack approach; more than that and it can get pretty unmanageable when you go to re-install them.

If a large number of consecutive leaves are loose, they can be dealt with all at once but by a slightly different method. By jogging them up at the spine edge and holding them firmly, an adhesive-charged brush can be raked across the spine edge of the group, allowing adhesive to barely run into the spaces between the leaves and over the outermost pages. Skilful execution of this procedure requires a little more experience than the stack method, but it is by no means difficult.