Affiliate Marketing Secrets

I am a beginner investor, but I am quite successful. I make around 5%-10% daily profit from my whole bank and rarely have a negative day. My secret probably relies on my bank management: I have extensive excel calculations that I gathered in 4 years of market study and even invented a profitable system myself.
My problem, though, relies on the withdraw of the profits. If I withdraw them, I will lose bank capacity to make more money in the long term. But if I never withdraw any, I will never really profit from my efforts.
When should I withdraw?
1) In a time basis (monthly for example)?
2) In a profit basis (Reaching for example 200% of the initial bank)?
How much should I withdraw?
3) A specific amount?
4) A percentage over the total bank?
5) A percentage over the initial bank?
6) Also, is there any formula for my answer, theoretically accepted by professional investors?
Thank you very much for your answers.