Change Colour of Hex Outlines ?

[LFDLM]

You're right, it's hard coded, we can only deactivate "Settings/Hexes outlines" and use a solution like the one I'm proposing. There are several mods (for NB, PC, etc.) where has done what I suggest. It's not "make" a whole new sheet, just put some lines on the one existing.

But I'm well aware that this is a palliative, not a real solution :(

Gotcha, thought for a moment you knew something I didn't, but checked and couldn't see how to do it other than adding a one pixel line around each graphic, which would look weird too!

I know nothing 

Well, not so weird, it can be well done, look at this napoleonic mod for example :