UPDATE:
After some testing I come to the conclusion that it is beneficial to change the condition for the Position Close.
Previously the position was closed when the Stochastic K-line was crossing into Overbought (close longs) or Oversold (close shorts) areas.
But when looking at the historical trades, I found that quite often positions were closed too early and additional potential profits were wasted.
So in the new version the position is only closed when the Stochastic D-line is crossing into Overbought/Oversold. This has the effect, that the positions stay open longer as the D-line will reach the closing zone with a delay (in the default settings the D-line is a 3period SMA of the K-line). This has a chance to be beneficial as in trending markets the Stochastic can stay oversold/overbought for some time. As the positions are anyway only opened and staying open following the general trend (as determined by the EMAs), the downside risk of this adjustment should not be too high.
Please check it out yourself - and let me know in case of additional improvement ideas - especially if anyone has an alternative idea for a more ideal position closing (trailing stop? etc.)
PS. Yesterday with default settings (BTCUSD on 4 HR timeframe) the 7th trade of 2020 was closed in profit. That makes it 7 out of 7 in the green this year.