[Samba] Understanding security

[betty Snoop]

I think I just got Samba authenticating properly with Active Directory.

So far in my smb.conf file I have the following.  It's just an example to
allow one group and one individual user access.

[Engineering]
   comment = Engineering
   path= /home/Engineering
   Valid Users = @MYDOMAIN+Engineering MYDOMAIN+username
   writable = yes
   browseable = yes



My question are:

1.  What should I set the following to so that only those who should have
access actually do.  I am confused which ones take precedence and which ones
should be used to ensure maximum security.

read only
writable
browseable
public
write list
etc

2.  Referring to the Linux directory, who should be the owner of each shared
directory?  Can it be root with chmod 777 since no one will have command
line access to the machine (ie.  users only accessing it via Samba).