Ah damn, I never posted that bit about the projection.
Well, basically you are slightly screwed. About 0.2 bumparelles, which isn't life-threatening. The map is what cartographers call in the "oh god what are these people doing here" projection. The simplest way to fix this is to stretch either the horizontal or vertical, or both axises so that their ratios are two to on, and then fix the poles. Here, you'd have to either fix the north pole by either creating a northern coast on the northern continent, or streth the northern bits of the northern continent so that covers the whole upper edge of the map. Let me show you what happens with your current map:
Huh, it doesn't actually look that bad.
It's kinda.... Alright.
well. You could probably just adjust the map so that it's 2x1, and then it's propah equirectangular.