Mine is not that severe, but with the varying thickness of the lens and the variable recess of the tip, it is not flush. I have stopped short of the precision you mention, but was thinking of leaving the tip recess even all around and then shimming up the lens as needed with a felt backer. After all, a replacement lens will have a different thickness profile.
Good solutions are awaited.
“I often say that when you can measure what you are speaking about,
and express it in numbers, you know something about it; but when you
cannot measure it, when you cannot express it in numbers, your knowledge
is of a meager and unsatisfactory kind.”