You can set up multiple parameter for both events. Volume Impulse :
Volume Period : Lenght of the average volume calculated.
Volume Multiplier : Factor to compare actual volume with average volume.
Engulfing Pattern :
VS avg body : Let you chose to compare body candle to average body of the last few candles (define with parameter : lenghtSizeAvgBody), otherwise it will be compared to the last body candle.
Engulfing Multiplier : Factor to compare and validate the pattern.