I did the DMARC stuff too. It's working great. I'm low volume tho, and there is never UCE sent from my setup.
Also did you have to research your IP/domain that your VPS sits behind? Domain blacklists, and avoiding them, seems pretty straightforward. But I've heard mixed things about VPS ips, some mail services could block whole networks from VPS providers while others don't care as long as you don't spam?