It can be mathematically proven that investing a percentage of your profit, as most traders do, will eventually cause a margin call with 100% certainty. This is especially a danger of automated systems that you don't observe permanently. You need to invest instead an amount that grows slower than your profit, such as the square root of a profit percentage.

Reinvesting is not implemented in Z1/Z2 due to the $7000 limit. That's not enough for properly reinvesting. The "Zorro S" version will have different Z1 and Z2 systems that reinvest.