9.2.0.7 to 11.2.0.3

Its a 9i database (Solaris OS) of size 475G. In development environment, i patched it to 9.2.0.8 and later upgraded to 11.2.0.3 with minimal issues. I haven't received any complaints from development folks so far.

We considered "Clone Database" approach in 11g Grid Console as another attempt to clone and upgrade the production database to a different server. 11g Grid control has limitations in identifying 9.2.0.7 oracle software. 

I am considering export/import method as another alternative. The plan is to create complete export dump of schema and directly import into 11.2.0.3 Oracle Home. Is it a proven approach? One of the tablespace with mostly table objects in 9i database is spread among fifty plus data files of size 8G. Going forward into 11g version, are there any recommendations concerning data file sizes (bigfile tablespace vs Normal)? Is it a good approach to have few data files of larger sizes?