You need to set "Minimum Win / Loss trades ratio". Its formula is:
Win/Loss Ratio = Winning / (Winning + Losing) trades
So, you need Win/Loss Ratio = 3/(3+1) = 0.75

This limitation works together with the OOS option in the Settings panel.
"Filter bad OOS performance" limitation makes Generator to refuse strategies with net balance lower than extrapolated balance line with more than the selected deviation percent.
For example:
[edited]
Lets the starting account is $1000;
Balance at the OOS bar is $1500;
OOS bars is set to 30%;
"Bad OOS performance" limitation is set to 10%.

First we have to extrapolate the balance chart to the end of the testing period.
1500 + (1500 - 1000) * 0.3 = 1500 + 150 = $1650
The theoretical net balance must be $1650 if the pattern of the balance line remains unchanged for the period of OOS.
10% of $1650 is $165, therefore, the minimum allowed final balance must be equal or greater than $1485.
The purpose of that limitation is to reject strategies with high profit till the OOS bar and big losses after that.

Please give also more information about the "Filter non-linear balance pattern" feature. I have already read the user manual, but I would like to understand the feature more deeply.

What would be a reasonable number of checkpoints. It defaults to 1 but I presume we would need a lot more than that.