Oracle Database Discussions

I will be implementing Unicode on a 10g database, and am considering using AL32UTF8 as the database character set, as opposed to AL16UTF16 as the national character set, primarily to economize storage requirements for primarily English-based string data.

Is anyone aware of any issues, or tradeoffs, for implementing AL32UTF8 as the database character set, as opposed to using the national character set for storing Unicode data? I am aware of the fact that UTF-8 may require 3 bytes where UTF-16 would only require 2, so my question is more specific to the use of the database character set vs. the national character set, as opposed to differences between the encoding itself. (I realize that I could use UTF8 as the national character set, but don't want to lose the ability to store supplementary characters, which UTF8 does not support, as this Oracle character set supports up to Unicode 3.0 only.)

Thanks in advance for any counsel.