Thanks for the response.
Maybe it’s as a I feared then, that the load time is simply too slow for my uses. Your tips make sense, but also as a photography gallery those are working against me, since I should have a fair number of photos and have them be nice and pretty and a decent size.
Just so I know… when I use the standard woocommerce product display, it loads nearly instantly, so what is responsible for the difference in time? Is it your plugin sensing the browser size etc and writing the javascript based on that?