I would make a PS for every meal you plan to eat, you can always cancel them if you change your mind. We went last year December 27 - January 4 and we were so happy we always had a PS since the wait times for walk-ins were usually huge, and we never ate at peak hours. We ended up using all of them (we had 1-2 each day, a late breakfast/early dinner combo usually) except one member of our party skipped dinner one night. It was also much easier for us to get more done and plan our schedule that way, since we knew exactly when we'd be eating, and aside from the FDP we never waited more than about 5 minutes for our table.
Oh, I almost forgot! We used EMH everyday (except NYD) and I definitely recommend it. I know it's tough to get up that early, especially since it was so cold every morning, but we'd get so much done during that time that it was definitely worth it. For us, EMH started at 7am since most parks opened to the public at 8am, so we'd usually arrive around 7:00-7:20 (depending on AKL transportation, which was horrible 12/27-12/31, when we switched to the GF). Between the time we arrived and about 10:30-11:30, whenever our breakfast/lunch PS was, we'd see most of what we wanted to for that park. Then we'd stay till around 2pm, go back to AKL and nap, then head our around 5 to whereever our dinner PS was and then stay in that park, or whatever one we were closest to if we ate at a resort, until around closing time. This plan worked great for us and we say every attraction/ride at least twice. It also helped that we were in the parks 8.5 days, so we didn't have to rush, and since you'll be there longer you can take a slower pace too.
We had already done the CP once before so we skipped it this trip, but one thing I would suggest that is different from just regular park attractions is to visit the resorts to see the holiday decorations. The GF in particular was beautiful with it's huge Christmas Tree and gingerbread house. AKL, BWI, and YC were also very pretty and I've heard WL is great around that time too. It definitely breaks up the day and gives you some relief from the crowds.