I'm finished a first draft which can be viewed here:
https://the-fall-of-brekhan.obsidian...mbat-logistics. The main changes are references to distance from a town or city that can provide supply, and speed while on the march. Both of these apply a multiplier to the LS needed to keep a force in supply (but doesn't increase the actual maintenance cost of the unit).
The major value I'm not sure about is the size of town or city required to produce a certain amount of supplies without paid intervention.
Right now I've got it pegged at 1 LS worth of supplies is produced per 50 people, based on very rough estimates from old medieval battles (involving ~3000 people per side) and sizes of major capitals (Paris and London, ~50000 each). Let me know if you think that's about right, overly generous, or still not enough.