Regarding resupply as a means of defense.. what if each load of sups reduced damage by a fixed percentage, such as 15%, rather than 10 minutes? That way resupplying would most benefit when towns are down extended periods, such as 100+ minutes.
Interesting approach. Let's do the math for resupply by 1,2,4 players respectively and a driving duration of 5 minutes.
First, a town at default downtime.
Second, at 60 minutes downtime. This is about a rather typical maximum downtime we currently encounter in AHIII, since the cities are far less attacked & destroyed than in AHII (except for Buzzaw)
Third, 180 minutes of downtime for the Strats
EDIT: Corrected the third chart.