Tablespaces and indexes

I'm trying to move over 50 tables (several over 500MB each) from a 7.4.5
database to 8.0.1 on a regular basis during system testing. (The 8.0.1
system will become the production system soon, probably next month.)

I'd like to have the data table and its indexes built in separate tablespaces
on separate physical drives. The 'default tablespace' parameter appears
to apply equally to both the data table and any 'create index' commands.

Editing the .dmp files to insert a tablespace clause in the CREATE INDEX
commands in the .dmp file is impractical because of their size, any
suggestions how to automate this?

Related question: Once I switch the 8.0.1 system over to be the production,
can I reverse the direction and restore .dmp files on the 7.4.5 system or
are the tablespace terms in the dump files going to cause problems?

Eventually the 7.4.5 system will be upgraded to version 8, but that may not
happen for a couple of months.

Are there any plans to have a separate 'default index tablespace' parameter?
--
Mike Nolan