Just some random thoughts because figuring all this stuff out and sometimes being frustrated by it is what I'm most enjoying and I don't agree that the mod is f**ed up. What's required is a strategy catered to the new regime. Finding this is, however, quite a bit more difficult than in the past.
Seems to me that there are two things you have to take care of simultaneously: food for your troops and rations for your troops.
Food ain't rations and rations ain't food.
Food follows mostly the old rules. Rations work according to phase 2 rules. These systems run parallel with each other.
So, as far as food goes, you still need to provide one food per recruit/civilian. Under the classic outpost system, half of a vassal's food production is available to feed your troops. (I actually think it's half the vassal's surplus food production.)
This is also why I imagine Ag plots
in outposts only produce half their normal production. If they produced their full amount there would be no reason to bother with vassal settlements.
So if you've got an Outpost with 15 troops you'd need a vassal or vassals that produced something like 30 food surplus
. Surplus would be after the each vassal's own food was taken care of and after any SS dynamic needs are accounted for.
If the vassal had a population of 15, I'd guess this would mean you'd need total food production there of at least 45 (even more if there were any leveled residential plots) just to meet the bare food needs of your 15 troop Outpost. That's basically 4 regular level three Ag plots--just to get your starting 15 troops fed. Whether those same 4 plots provide enough rations is another concern.
Rations, however, are only determined by Ag plots and mainly by their level and whether they are in an Outpost or a Vassal. The actual output of the Ag plot doesn't matter in regards to rations.
Whether a level 3 Food plot produces 10 food or 20 food, it still provides the same amount of rations. But Ag plots in Vassals, due to the vassal production bonus, produce more rations at each plot level than the same plot in an outpost.
If you are vassalizing City Plans (I'm not), I can imagine certain inefficiencies.
A city plan is either designed to be self sufficient or not. If it's not and it specializes in maybe one area--Commercial, Industrial, Agricultural, or Recreational--then it is meant to be networked with another city plan or settlement that provides for what it is lacking.
A self-sufficient city plan may or may not produce enough surplus to actually feed your troops. How much of surplus, if at any, was it designed to produce?
Does the CP vassal have a bunch of leveled residential plots? If so, these plots, due to dynamic needs, require food in addition to what the settler requires. This will reduce not ration production, but the amount of surplus food available to actually feed your outposts.
And also keep in mind that Civilians require rations just like recruits do. So the more civilians you have the more strain you put on your available rations for new recruits. If a City Plan vassal has recreation plots, then these civilians are using up rations without producing any W/R/E. (Although, the happiness they produce probably should shouldn't be dismissed out of hand)
If you vassalize a specialized CP, what happens when you remove it from it's support network? Now your Outposts and other Vassals, in addition to covering their own needs, have to support this one as well.