As I mentioned in my current WIP thread, I'm having trouble turning my maps of individual continents into a single world map. Part of the trouble is, arguably, my own making: I used different projections and parameters for each map, in order to minimize distortion on the individual maps. I've tried using ReprojectImage to convert unlabeled versions of my maps to equirectangular, but due to its limited options vis-à-vis projection parameters, I've so far been unable to avoid introducing distortion compared to my original equirectangular sketches of each continent. It appears that the only way to match the original sketches as closely as possible is to use GIS software, hence the thread title - and my need for advice.

I have limited experience with QGIS and MicroDEM from unrelated hobbies, but not in the area of converting between different projections. An earlier experiment in georeferencing a map introduced some unexpected distortion, perhaps due to my choice of datum, or having too many control points. What I've read about ISIS3 makes it look like it might be better suited to the task, but it doesn't run on Windows, so I can't currently run it. Is there an alternative I can try? Or is there a way to properly georeference a map, such that errors and distortion are minimized? What would those of you with experience in GIS do in my position?