Hi Panagiotis,
thanks for this proposal.
I don't have a strong opinion (yet) on whether we should allow to
indent to a custom column by setting org-adapt-indentation to an
integer. My gut feeling for now is that this is too much, but I
don't want to dismiss this possibility completely.
That said, the new customization values for org-adapt-indentation
have not yet been released, so I suggest continuing the discussion
for after 9.4 has been released and for after org-adapt-indentation
has been more widely used in its current (from master) state.
Thanks,