Merely maintaining the size of the gap is already a success for Switch against the DS during these past six non-holiday months for both. I still expect Switch to fall behind by 10m+ sometime over the course of the next 18 months, but that's a manageable enough deficit to beat the DS in the long run.
That sounds about right. In 2 months these two totals are going to be close, but then the DS is going to pull massively ahead on it's next respective holiday season. But after about a year and a half from now, DS legs buckle pretty quickly. Switch just needs to stay "close enough" for now and have decent legs at the end. If so it will outpace the DS's total.