Parameter book% as % of balance

[Dublin_Flyer]

I'd like the possibility to use a balance %age as the stake by book %age.
Example:
I want to dutch runners 1,2,4,7 and 9 using their book percentage using 1% of my balance. Opening balance is 1000 so using 1%, I'll have the book percentage of those runners, say 38.6% dutched of 10, so there's 3.86 staked.

Scenario A: Winning bet, then bank is 1010 or thereabouts and the book percentage of 1% is now 10.10 so the book percentage will be of that amount.

Scenario B: Losing bet, then bank is 996.14, so the book percentage to be backed to for the next bet will be 9.96.

Not sure if I explained it properly, basically it's to increase the profitability of winning streaks by making use of the small fractions.
If I gave you 1000 on Dec 31st 2013 and said to make 1% profit daily, then by this friday the profit would be over 10 thousand! Increasing to 35 thousand by Dec 31st 2014, nice New Years Eve party then.

Not sure if the phrase is accumulative or exponential, or neither of these, but if you get the gist of what I mean then you'll understand.

I know this is probably possible to do in Excel, but my familiarity with Excel is quite limited, I get my daily list of qualifiers from Horseracebase and order it the way I want, can do some basic calculations, that's about it.

If anyone knows the idea of what I'm talking about, feel free to explain better or suggest a way to achieve it.