Neat project! It's an understandable limitation you had to commit to, but I'm curious how you've found the distortion away from the equator with Mercator. Probably not really noticeable in any major way within the arctic/antarctic circles but obviously closer to poles it's going to get quite wonky.

Distortion isn't too bad until you get to the arctic, but by then its all white so you don't really have a reference point to judge against anyways