We ended with two charts, essentially, that told us how long it takes our craftsmen to gain experience in their craft, and how long it takes those pesky adventurers to come in and pay-to-play with a Focused Apprenticeship.
Let's combine the two tables.
You'll note some numbers have changed, I've put this into a spreadsheet so the math's right this time ;)
From left to right, the monthly income level if you're self-taught or in an apprenticeship, the time it will take you to advance from "nothing" to each tier for the same, then, the cost for a focused apprenticeship if you want just the identification proficiency throw, or the ability to actually work the trade. Lastly, the 'Profit' line is what the tutor makes off of your labors. (UPDATE: Whoops, I'm going to have to go back and fix this. That should be Time * Monthly Income)
Art, Craft, and Performance all use the same income level, so it makes sense to combine them - a well crafted sword is as much art as a statue, and performance is art, so we're all on the same page.
Again, my assumption with how I'd use this is as a complete replacement of the 'profession' proficiencies in ACKS. A starting PC would perhaps choose a background, which may include being at a Journeyman level of skill in some profession - the young warrior-weaponsmith or rogue-dancer out to make his or her mark upon the world, and maybe survive long enough to make it to Big City and train with the masters of their chosen craft.
Somewhere in here there's a story of a largish lad who started out as an limner of illuminated manuscripts before his clerical betters found out he was good with a sword and sent him off to be a paladin, and as soon as this evil is vanquished he's going to trade his sword for his brush back.
Anyway - to the rest of the proficiencies, starting with Animal Husbandry, for which I made up monthly incomes.
Note the 'Value Multiplier' cell. The way I did this has an unintended side effect where the more you make, the quicker you advance, and that's not always the way it should go. That multiplier raises the cost of the "Identification Skill Only' training, which then (because of the spreadsheet setup) extends the length of time it takes to go through each level.
Here's where that starts showing up - takes a bit longer to be a master Chirurgeon.
That multiplier system falls apart with the next skill, Knowledge, since Sages make so darn much. It took less time to go from Professor to Sage than from Student to Professor.
So I fixed that thematically, by making Sages parsimonious with their knowledge after a certain point. They're not going to train you past Professorial level, as you're going to have to make your own discoveries and further the field on your own after a certain point. It's like getting tenure - they'll still tutor you, but it's still gonna be a long slog to the end. Read PHD Comics.
For myself, I'm also combining the three skills that map back to the old 3.5 concept of Knowledge(Arcana, Divine, Nature) into Knowledge, since I don't see why an old Wizard, Cleric, or Druid ought not be Sage-level in their various spheres if they choose to be. I also realize at this point I've gotten Naturalism and Beast Friendship all mixed up in my mind, so I'd probably just punt and combine them under Knowledge(Nature).
It's likely you could also roll Military Strategy into Knowledge, trading the income levels for the mass combat initiative bonus. You could then either hand wave the advancement, or, convert the necessary GP milestones into "units defeated" or "battles won", perhaps.
Alchemy had the same problem Knowledge did with the pay rates - I fixed it here by reversing the order of the training times.
I dropped both training and tutelage here after 'Sailor', as once you're experienced enough to be a Captain you're on your own. There's an undocumented step in here where our intrepid Sailor took Navigation and earned 25 gp/mo for a while, which probably got him to Captain earlier.
Of course, that also means someone has to give you command of a ship, or you've commissioned your own, to be a Captain. I'd assume here the ~7 years spent on deck gets you to the point where you wouldn't be bad at it.
Alex, if you read this, I hope there's enough economics around running a fleet of ships (maintenance, ports, etc.) in Domains At War that I can take that above table and run a combination of D&D and Sid Meier's Pirates!.
A wet sandbox, as it were.
what with the making-up of income levels and the fourth 'tier' to get to the level required to be a Specialist. It's interesting to note that since you have to take Engineering 4 times to be a working specialist, the "identify engineering" portion of the proficiency is on a roll of -1+, which is fun to look at.