Regarding durability. One of the things that lured me into buying roto wool was the thought that it could be an easy way of applying a thin layer of really hard wax to the skis, and that this could help durability.
I'm not that concerned with ulitmate glide, but hate base burn. But at the same time I don't like to work with really hard waxes (CH3-4-5) , brittle, flaky and if the skis are dry to start with as they often are, a softer wax should be applied first adding yet another step.
I hot wax when I have time, and often not able to get it right for the conditions. Usually use LF6/CH6/HS6 or LF7/CH7/HS7 for the hot waxing. If getting icy or cold and abrasive conditions I would wool on some CH5 or CH4 on top of the softer wax. If it gets warm and wet, I would spray on some HS8 on top of the harder wax.
But in real life I don't really have much time to wax skis, even with spray and roto wooling, so have not gained enough experience to tell if it's working or not... I do proritize to sharpen edges and generally find that's more important than waxing to have a good day while skiing gates. But the bases suffer...
Today I'm just proud I managed to clean and apply "Swix Base Protection Liquid" to a whopping 24 pairs of skis ;-)