This is well after leaves have hardened off. This of cousre will depend on your location. Here in the Northeast US, I usually defoliate around mid June. You also want to ensure the tree has enough time to put out a new crop of leaves well before fall sets in so careful in not doing it too late in the season.
Damn that’s a healthy tree. Shows what leaving it alone for several years does for a tree. (I’m referring to before before you acquired the tree)
I think it helped that you only did the severe root prune on half the tree first. I think it would not have recovered as fast if you had done the whole tree.
Patience is a virtue.