For my current (first) novel, I decided to use the date as my chapter markers. Since so much happens in a day around the world, I thought it was helpful to the reader to know for sure when we had moved to the next day. That way when I returned to a scene in one location vs another, I would not have to blend in something to the scene about the day change every single time. The chapter marker automatically did that for me, keeping it more streamlined in my view.
If that turns out to be a newbie writer mistake, I can certainly make adjustments easily enough, but I think it helps me unfold the story one day at a time.
Within the chapters between scenes, I am just using a second double space gap. That seemed to be common enough in this genre.
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