>Maybe invite a photoshop or drawfag around. I dunno
It's not that complicated. All that's needed is to get a base map like this and get clean borders with pixel bridges to islands/clearing islands, so that a single use of the bucket tool will change a territory's color. For that it is also necessary that the territory's name be within a bordered box. Smaller bordered boxes can contain the width numbers but width can also be represented more directly.
That said the map is of secondary importance, mechanics have to be figured out. I've described a model for casualty determination, but not for whether or not the attacker gets to advance. Hence I propose:

Combat has two parts, Attrition (casualties) and Maneuver (conquest). Both are determined by the same d100. There is a Base Conquest Value (C), the same for the whole game. It is somewhere on the 50-90 range. Everything else aside, to advance over a province and have surviving defenders retreat the attacker must have a dice roll higher (equal or higher?) than it.
The attacker can have a better chance as other values are subtracted from it. The first is the Outflanking Modifier (which I believe should be calculated over CDS, not TDS). I also wonder if another modifier based on the ratio of total strengths should be used, so even without outflanking an attacker can have a better chance of going through with enough strength; this should, however, be a reduced effect, multiplied by another parameter, Maneuver Usage of Total Strength (MT), of, say, 0.2. Gut feeling says a higher MT (easier for a numerically superior attacker) should be paired with a higher C (harder for attacker overall).
Further, there is a Lowest Conquest Value (LC), even with excellent odds sometimes the attacker just loses. If C subtracted by the other two values goes below LC, LC is used.

So the procedure is:
1d100 > C - O - [(TAS/TDS - 1) * MT] > LC = Attacker advances over the province, defender retreats. Retreat procedure is something to consider, in realtime the defending player would decide where to.
1d100 < C - O - [(TAS/TDS - 1) * MT] = Attacker doesn't advance.
1d100 < LC = Attacker doesn't advance.

>A 1-2 hour back and forth thread with screencaps could be good. All happening on a specific date everyone playing feels comfortable in tbh. Let me know what you think bernds!
I want this for a slow burn game potentially played over months in /kc/ but it should work just as well for that.