Yep. I have just symlinked my /home/user/30-user.policy file to the /etc/qubes/policy.d/30-user.policy file as well. In contrast to your setup, I will be collecting ALL my mods to the policies in this single file (I will be using comments in that file to structure it). I will also move the contents of the split-ssh and split-gpg configs into my 30-user.policy file. This should make migrating my dom0 to a new physical machine a breeze.