samba - Sep 2007 - moving from local profiles to roaming profiles

Hi,

I'm runnung samba 3.0.24-6etch4 as PDC with local profiles in a 100%
Windows XP environment (about 250 clients). Now I'd like to use samba's
roaming profiles feature. I'v deployed "User Profile Hive Cleanup
Service" on each client and plan to add the following entries to my
smb.conf:

[global]
....
logon path = \\server\profile$\%U\%a
....

[profile$]
        comment = Network Profiles Service
        path = /vol/profiles
        read only = no
        create mask = 0600
        directory mask = 0700

Did I forget something or is there anything special to pay attention to
(read something about cache files)? 

And is it possibility to start with a small number of users? If I
understud the documentation correctly, the above configuration would
affect to all users when log in/off the next time.

Thanks,
Marcus