I would probably do nothing to this tree untll established?
Big tree. Let it get settled
After putting it in the pot, all I have done is cut off two very long stringy branches and fertilize with fish fertilizer.
Well, also I have pulled the dremel out and ground some dead wood off. It is hard as a rock.
One possible issue is rain because it won't stop, but it sat in the soggy ground forty years and it is hard to think pumice-kava rock-akadama doesn't drain.
Ok, let it sit and fertilize lightly.