Change default permissions for log files.

I am in the process of securing a Solaris 10 Server.  As part of the hardening process I would like eliminate world/other permissions on log files (e.g. /var/adm/messages). Now, at first glance this may sound easy simply run chmod and remove the perms.  However, it is a little more complicated. Logs such as lastlog, messages, syslog, wtmpx are created by the syslogd process ( I believe) so I need to determine how the default umask is set on these files and how do I change it.

So, if anyone can help me determine how the following log files umask is set and changed I would greatly appreciate it: