Reduce Header Height

I'm using GP Premium and the header plugin and I am having issues with the header height. So far the height seems to be generated in the inline css and the only way I can override it is using the following css:

.generate-combined-page-header {
height: 60vh !important;
}

Is this correct? I can't find any settings to change.I thought it was under Page Header > Image > Resize Image > Enable > Image Height: 600px. But this doesn't do anything??