GPP assigned to Users OU but use Item-Levewl targeting with Computers?

I have a group of machines that I would like to have Lync 2013 NOT autostart.  I can delete the registry key from the reference section below and Lync 2013 will not start (as expected).  These machines have 10-20 unique profiles that also need this key removed.  I was considering creating a Group Policy Preference (GPP) and assign it to the Users OU (as this is a HKCU setting) but use item-level targeting to a security group containing the computers that need the autostart disabled.  This will keep the registry key from being removed from the users primary computer but if they log into one of these machines in the security group it WILL be removed.

Questions:

Is applying the GPP to the Users OU and using Item-level filtering to a security group populated with computers the best approach? 

Will the GPP get processed by all users every time they log in even if they aren't logging into one of the computers in the security group?  Note:  The Users OU would contains all users in the company.

Reference:

http://blogs.technet.com/b/rischwen/archive/2013/06/20/lync-2013-client-auto-start-registry-key.aspx

HKCU\Software\Microsoft\Windows\CurrentVersion\Run\Lync

Thanks