Mine is only a foot tall. I just feed it compost/manure tea periodically and it seems to do fine. It's just a white sapote, although much cold hardier. Treat them like citrus and I think they will do fine.
The mother tree for most of the pringleis is (or was) at a nursery a few miles from me. I say was because the nursery closed and I think the property is being "developed". I've gone by there trying to contact someone but no luck. D