The Natural Philosopher writes:

Does anyone have recommendations for optimum ventilation?

put it on bricks remove all the bottom and fit some expanded steel mesh
flooring inside

Think I'll try enlarging the side holes first; I'm trying to keep the
assorted small unburnt (green) twigs etc. inside for easy removal.
Of course if I got it to burn well enough, even the green stuff should
be reduced to ash.

--
Windmill, Use t m i l l
@ O n e t e l dot c o m
J.R.R. Tolkien: All that is gold does not glister / Not all who wander are lost