I couldn't agree more with what Yates said. Osta first is the better idea, IMO. If you run the DMZ first, you will most likely be heavily supressed before you get to your Osta portion of the cycle. It will make it more difficult to enjoy. Although, you could stack the Osta with something else as a base...
Before my last Cycle, I ran Ostar1ne @ 20-25mg (w/ IL XI-KT & Transform) for 8 weeks before heading into a Diabolix cycle. In hindsight, that amount of time on Osta was not needed before the AAS cycle.
I am doing the same again starting next week. I am panning on running Ostar1ne for 30-35 days @ 15-20mg per day, before my Triumph (and something else) cycle. My goal with the Osta warm-up is to drop a bit of bodyfat before I hit the Triumph. Osta really shines it a cut/caloric deficit because of it's muscle sparring properties. I will eat at maintenance and focus on a lot of fasted morning cardio (5-6 days/wk) to hopefully drop a bit bodyfat before the cycle begins. The Triumph should really shine with a lower bodyfat level.
I do get that some people use Osta as a bridge into PCT but I just think using Osta as a bridge into an AAS cycle makes more sense. Moderate supression, heavier suppresion and then quickly into PCT.