What you see is about as well as I can do - basic bitmaps. I’d need to collaborate with an experienced graphics artist to make it look commercial.
However it isn’t the exact scheme I would use; one main difference would be that land territories would be plain light green, with perhaps some mountainous areas in grey, deserts in sand colour and so on.
A shaded border around the outer tt is enough to denote starting national control, indeed on the official 1914 map the presence of flags and control markers makes the coded tt colours redundant as well as gaudy and distracting.
Naturally the African borders would follow contours rather than the quick straight lines I’ve used.
Actually, I’m quite happy with the diamond layout for this game, as long as the western front areas are big enough, and there’s room for Mexico in the eastern corner.
I also dislike the stippling effect on most maps; if it doesn’t have any effect its just a distraction.