Well, at first, I knew my chapters wouldn't fit within the character limit, so what I did was to fragment them in four parts.
I guess for Tapas layout - and Tapas' goal as little text snacks - this way is better.
And doing that way, you bring a lot of good things for your novel:
- the chapters feel smaller, and people tend to be convinced to read something small than a text wall;
- you can update a lot more that way, bringing more views and likes to your work;
- you can breathe a lot more between chapters, so you don't have to commit doing 15.000 characters to every single update, but only, let's say, a quarter of that.
The size of your chapters is entirely up to you though.