4 - Underhill and Wilber
I would see my approach as being temperamentally similar to that of Evelyn Underhill whose classic work "Mysticism" I have always greatly admired.
Though Wilber in "Integral Psychology" suggested that Underhill’s treatment - as representative of the Christian tradition - was broadly in line with his own, I would fundamentally disagree.
Underhill - whatever her limitations - uses an inherently dynamic approach (that is suited for dealing with the integral aspect of development). By contrast though Wilber’s approach is superb in its own right and unrivalled in terms of its comprehensive detail, it is somewhat mechanical (being suited for the differentiation rather than the integration of development).
For my comparison of the two approaches click on
Integral Approach: A Comparison of Underhill and Wilber