Daniels specifically calls out how to set up your plan with a graphic with the various phases laid out. Isn't his plan generally a 24 week buildup?
I don't have his book in front of me, but I think it would work out to 4 weeks in each phase. You'll want to verify with the text because I don't have it in front of me. He might have said something like 6/4/2/4 for each phase respectively but I can't remember.
I believe he would say Phase I is the most important, and if you are coming off of an injury I would definitely agree with that. Going into phase II depending on your injury you'll also want to be cautious, especially if in new mileage territory. If you haven't been running for a while due to the injury, you may want to extend phase I even further and focus on just finishing without worrying too much on the workouts, or find a later marathon to get a better buildup. Good luck!