Personally, I think it depends on how much you can roll a story. Dhaval and Ronin, two of my characters, are a good example of a bad-case. Dhaval runs on minimal funds/promised wages per job, so he has little income beyond post-jobs. It essentially allows him to keep everyone contracted, manage the ship... but only if the crew does good.
Ronin, on the otherhand, has taken out loans in preparation to repair and fund his initial ventures. With him, the group'll have fixed amounts due to it being bounty-oriented.
Then there's someone like Xun. Just operating the Reva Maya sustains itself due to passenger rent. Additional funds (though there's not much necessary in Iroma plots) are really as simple as doing work.
So it really boils down to the set-up you have. With a full-blown faction, I think book-keeping is more necessary. With a simple corporate plot (initially, as it remains a small factor), I think you don't really need to worry much on exact numbers but have a range (100,000-300,000 KS, for example) to assume your current wealth within.