Have you considered mounding soil or soil/compost over the roots
instead of burying the roots, or burying part of the roots and
mounding over the rest of the root? Then, the clay pot syndrome may
not cause much of a problem if any and this assures that the crown is
prevented from rotting in case of an extended wet period.
Just wondering if you'd considered it, I know it is often recommended
for home growers but don't know if there are any glitches for
commercial growers, such as mid summer drought and the task of
watering 200 newly transplanted trees in mid July whose roots are
somewhat above the surrounding soil line.
Kevin B