Change responsive height?

Unfortunately no easy way.
The container min-height is not set via predefined CSS code but is dynamically generated with JavaScript (jQuery) code when the page loads or whenever the window is resized. So if you have 75% min height set, this can change the actual pixels min-height calculated depending on the number of slides you are currently on screen, which in turn can change at different resolution.

So here is the JavaScript code within the /plugins/slide-anything/php/slide-anything-frontend.php file:

window.addEventListener('resize', sa_resize_slider_image_demo);
function sa_resize_slider_image_demo() {
	var min_height = 'aspect169';
	var win_width = jQuery(window).width();
	var slider_width = jQuery('#slider_image_demo').width();
	if (win_width < 480) {
		var slide_width = slider_width / 1;
	} else if (win_width < 768) {
		var slide_width = slider_width / 2;
	} else if (win_width < 980) {
		var slide_width = slider_width / 2;
	} else if (win_width < 1200) {
		var slide_width = slider_width / 3;
	} else if (win_width < 1500) {
		var slide_width = slider_width / 3;
	} else {
		var slide_width = slider_width / 4;
	}
	slide_width = Math.round(slide_width);
	var slide_height = '0';
	if (min_height == 'aspect43') {
		slide_height = (slide_width / 4) * 3;
		slide_height = Math.round(slide_height);
	} else if (min_height == 'aspect169') {
		slide_height = (slide_width / 16) * 9;
		slide_height = Math.round(slide_height);
	} else {
		slide_height = (slide_width / 100) * min_height;
		slide_height = Math.round(slide_height);
	}
	jQuery('#slider_image_demo .owl-item .sa_hover_container').css('min-height', slide_height+'px');
}

I’m assuming my workaround suggestion helped you resolve this issue – am marking this thread as close.