As things currently stand I have an assumed 6 magi, 5 companions (Aegis has no expenses), 1 specialist (teacher), and an income of 100 lbs of silver per year, and a rent of 25 pounds per year. optimizing required servants, teamsters, and laborers gives an annual expense of 61 pounds per year with 19 laborers, 10 servants, and 2 teamsters, or 57.5 pound per year if Aegis serves as cook 2 seasons/yr. Obviously some craftsman could be added that would bring the total cost down- if they provide more than 4 lbs in savings. These values do not include writing materials, labs, or weapons and armor. I will also note that there are still points available for boons to increase the base income, either by adding a secondary source of income or by improving the current source of income. The easiest place for the savings to occur would be in masons or carpenters, who would need a craft ability over 6 to achieve the necessary savings.
So presumably we can take the Wealth minor boon multiple times? Regardless a single wealth boon is a good option and we could maybe even use build points to start with additional money that we can use to establish an additional income source sometime into play. And there is of course always the magical option.
That would give us an income of 350-25% = 262 pounds a year to play with initially plus whatever we develop in the first year. This would save us using an additional boon for income but we would most likely have to spend seasons in game to develop our economy
Alternatively 2 minor wealth boons or a major wealth boon is 600-25% = 450 or 1100-25%=825 pounds/year respecticaly. These options would require significantly less economic management and building within the game but would cost us 2 minor boons or a major boon.
You can take secondary income multiple ties, you can only take wealth a number of times equal to the number of income streams you have...