Rescaling normalized enrichment score (NES)

Question

[CTLong]

Hi all,

I performed VIPER analysis to obtain transcription factor activity normalized enrichment scores (NES) corresponding my samples. I would like to plot a heatmap to show the difference in NES for multiple transcription factors. However, I have come across this problem whereby the range of NES goes from -15 to 15, but the NES difference between my two groups of samples are around 1 to 2. As a result, when I plot a heatmap, the activity differences between the groups are not obvious.

Is there a way to rescale the NES where it can be justified? I have thought about calculating the NES zscore or log normalization of the absolute NES score. Are these justifiable? Thanks.