Also, let's get started talking about world-trimming now. I feel like 1.9 will be dropping before the end of the year, and this is one more thing to get ready!
I've fired up Photoshop and started marking up a guides grid to represent the chunk files. Here's the main part of the world minus the long cardinal direction tendrils. Thoughts on this first pass?
Also, here's a copy without the red overlay if you want to make your own version:
https://i.imgur.com/XgawFwr.jpg