effective safe_mod configuration

Hello,

I'm trying to use PHP as a module, while maintaining a multi-user
environment. I figured the following out:

/var/www/ is the document root of the apache. PHP works as module and
is in safe_mode. Every user owns a directory under /var/www/ and has a
virtual host pointing to that directory with the following directives:
open_basedir = /var/www/user1/
safe_mode_include_dir = /var/www/user1/

Additional system programs can be made available with
safe_mod_exec_dir.

I think this should be an acceptable safe configuration, while
granting enough internal rights to each user.

Is this the right way or did I miss something?

Thanks
Klaus