On "King" difficulty, you're lucky if you can afford enough for 4 castle sections at once.
I found another ratio for "good":
10 diggers
60 carpenters
60 masons
60 quarriers
60 carters
60 smiths
40 labourers

If you want to make paying for them cheaper, you can by making masons work for 5.5 instead of 6 and input:
10 diggers
80 carpenters
50 masons
80 quarriers
30 carters
50 smiths
50 labourers

this is still "good'> I'd like an 'excellent' ratio that is around 350 workers so I can afford it on 'king'.

I know this is a really old thread, but I found a couple 'Excellent' ratios. With the following numbers/wages combinations, one only needs to pay 50 for 370 people (affordable even on King difficulty):

Digr 115 (or 120)/1
Carp 60/3
Masn 45/3
Quar 45/0.5
Cart 30/0.5
Smith 15/1.5
Labr 60/0.5

Another possibility with paying 61 for 450 people:

Digr 140/1
Carp 75/3
Masn 50/3
Quar 60/0.5
Cart 30/0.5
Smith 20/1.5
Labr 75/0.5

For having more men, one would need to increase mason salary to at least 4 (otherwise at most 50 can be recruited), and carpenter salary to 4, which immediately increases the total wage by at least L12. But then one can experiment to get similar ratios with bigger numbers (Digr = 2x Carp, Carp = Labr, Masn = Quar = 3/4 Carp, Cart = 1/2 or 2/3 of Quar, Smith = 1/2 Cart). I would be interested in the exact formula on these ratios, if anyone has the patience to test it out.

Oh, yeah, the manual is incorrect in stating that the wages are for 20 workers/month. In reality it is 10 workers/month.

Furthermore, the game has another bug: no money needs to be payed for archers. Ever. You can put their wages to L5, and increase their numbers to the max, and the money you spend on military does not change. You only pay for infantry.
Note, that to have 500 men as a possible max, you need to have a castle with at least 61 pieces.

And sometimes scenarios ask you to pay money, which is not deducted, and similarly, the scenario tells you that you will get some money, when in reality the treasury does not increase.

Edit: BTW, if anyone is interested in finding the exact rules for the 'Excellent' ratio, maybe this helps. I found my ratios by starting with a ratio of 4:2:2:2:1:1:0 (giving 'Excellent'), and then worked up the number of labourers and changed some of the other numbers in accordance to make the total wage lower.

My own experiments with this revealed that manual is indeed right and the optimal worker mix indeed changes by *stage* of your castle completion (there total of 3 I think); further, on multiple castles campaign, every map have them different!

I was going to research those, but get bored and annoyed with the game far before I get any clear, conclusive results. Further, for me it was just purely *academical* interest and frankly completely moot point as I quickly discovered a game breaking exploit and building the castle become a leisure activity after I already *won* the level before the first attack comes.

On Rhos there are only two stages, in the second stage e.g. the following ratio can be used:

Digr 35/0.5
Carp 65/3
Masn 50/3
Quar 65/0.5
Cart 65/0.5
Smith 15/1.5
Labr 15/0.5

On Arfon in the first stage the same ratio works as for Rhos first stage. For the second stage I have yet to find an excellent ratio. However, the problem may be that resources suddenly plummeted from the usual 6-8 to 0, so that may mean that no excellent ratio is reachable. I am not sure. I might just stick with good for the rest of this castle.

Honestly, though, I am not 100% sure that building is indeed faster with excellent ratio. I am starting to think that it has more to do with whether game speed is set to Laboured, Steady or Swift. The speed implementation is definitely buggy e.g. in the fights people move with exactly the same speed no matter how fast the days are ticking by.