ALTER TABLE SET TABLESPACE and pg_toast

We're storing tif images in a table as bytea.  We were running low on our
primary space and moved several tables, including the one with the images,
to a second tablespace using ALTER TABLE SET TABLESPACE.
This moved quite cleaned out quite a bit of space on the original
tablespace, but not as much as it should have.  It does not appear that the
corresponding pg_toast tables were moved.  So, my questions are:

1) Is there a way to move pg_toast tables to new tablespaces (or at least
assure that new ones are created there)?
2) Also, is there a good way to determine which pg_toast tables are
associated with any particular table and column?

Thank you for your help,
Martin