EODatabaseContext.Delegate

I have a particular EC save operation that needs to be reorganized
(deletes need to happen before inserts). I have found
EODatabaseContext.Delegate.databaseContextWillOrderAdaptorOperations(),
but I can't figure out how to get to an EODatabaseContext from my
EOEditingContext (EC).

EC.parentObjectStore() gives me an EOObjectStore, but then I couldn't
figure out what to do from there -- there is no obvious way to get at an
EODatabaseContext.

EODC has a static method to get the EODC corresponding to an EOModel and
an EC, but then I need an EOModel, and I can't figure out how to get one
of those from the EO I'm trying to save, though surely there must be a
way. Now, an EOEntity can tell you about its EOModel, but of course an
EO only gives you its entityName (a String), not an actual EOEntity object.

I'm flailing here. Is there something obvious I'm just not seeing? Is
the easiest approach a split my save across two EC.saveChanges()
invocations where the first one does deletes and the second does inserts?

TIA,

zak.