OATM uniform extent strategy

 In my first pass of the OATM (Oracle Apps Tablespace Model) utility in release 11.5.10.2, the database actually grew by over 30G to 285G of used space.  Not a huge growth, but not quite what I expeected.  This appears to be because we migrated to uniform extents of either 128k or 1mb and many of the empty/unused tables took a larger initial extent than they had before the migration.  So, I'm thinking of migrating by schema and migrating the unused schemas to tablespaces with small initial extents.  Has anybody else pursued a similar strategy?  That means that future DBA's might have the task