I'd go with something short. Maybe not even "11 pages at most", more something like 1-2 pages if you have some plot for them.
It is my point of view only, but I feel like gag of the day is not something satisfying. One day you have an idea what to draw, another 2 days you don't (because nothing is happening in your life except daily routine). You may draw a dozen of them, but in the end it feels like you did nothing at all, especially if those are 1-picture comic.
But no harm in trying for sure! Though I would recommend something with...some kind of plot, it doesn't have to be a completed idea even, just start and end somewhere.
Also if you are tired and unmotivated, maybe it's better to simply take a break! 