Crikey,
Long time...... please PM me

I no longer have your email address....
As you are a mapper, and others have the maps, clarification in needed.
To go with the 6m, 9m, 12m, 15m, etc maps, you must make sure that in the map.ini file containing the [map scale = 30] is changed to [map scale = 25]. This is a recent discovery and brings all to the correct scale. it was slightly off. So actually, different scales can be used 5m with the 30 scale, and 6 mile with the 25 scale. BUT we are going 6 mile on the same footprint.
In Napoleonic's, there will be some big maps for big battles.
Couple this with a new rifle range chart, and all will fit very nicely. The Naps are ok, The CW is lacking.
The mods you mentioned cannot be adopted as for the reasons you mentioned AND we cannot and will NOT RETROFIT old games and mods to another system scale. Both will work here.
Idealistically, the above "conversion" would work, but the correct reduction would have to be to the correct scale, (which it was not), and as you said a LOT of work to reproduce all spats, sprites, building stuff, as well as the entire combat and mechanics of the game would be a nightmare.
They are just Mods, not official. And, you would need to know what you are doing.
In fairness, the map scale Idea was discovered by John (Wrangler), I verified it, and Eric drew the first maps for TC2M.
Once I left Norbsoft, I had been running with it, and using my civil engineering skills to develop standards and technique. Randy has just tried to modify it.
Mark