This is similar to what we did at most stations where I worked (the ones that had music formats, anyway). At one, we went wall-to-wall with it on what we now know as "black Friday," but just for that day. Otherwise, we programmed similarly to what you suggest, and went wall-to-wall with it (again, in the case of that one station) about a week before the big day. I would be okay with SOME Christmas tuneage after the holiday, but apparently I am in a minority there. (But then again, I don't want to hear it between Halloween and Thanksgiving, either. We still have days with temps in the 70s and 80s that time of year! I may even still be doing yardwork during that time!)
You work retail? You have my sympathies. I remember being subjected to a lot of instrumental Christmas music back when I worked at Wal-Mart.
Back when I could stand to listen to top 40 radio, I liked the week between Christmas and New Year's because that was when the station near me at the time did its year-end-review, playing back the year's biggest hits, in preparation for the countdowns of the year's biggest hits. I always enjoyed that week!