I have been using a fair amount of Solda S30 Cold Powder as a base for other glide waxes. Our old snow in Bend, Oregon, is extremely abrasive and the S30 as a base layer helps preserve the wax, protect the base and enhance the glide. Pretty good stuff and it will not break the wax budget.
Solda S30 was initially designed for alpine skis used in races on artificial snow. That snow is often cold and is always abrasive. The powder was to be applied to the ski bases near the edges. It kept the bases from being scoured by the hard snow and helped the wax to remain in the p-tex bases. Soon, Nordic skiers discovered that it worked of cross country skis too. It was first used as a top coat in cold, dry conditions. If air temperatures are below -10C and snow temps are also cold in medium to dry humidity, this is a great top coat over a base of your favorite cold wax. I have used it at -15C on new snow over a base of Sold F15 Green and had slippery fast skis.
Since then I have learned of other uses for S30. In cold or medium humidity I use it as a base for other lubricating waxes. I start with a base of Sold Performance Green, scraped and brushed. I then apply a layer of S30 powder and iron twice, each pass done fairly quickly because I am using a hot iron. Then, while the base is still warm I lightly scrape it leaving a thin and powdery surface of S30. I then select the wax of the day, any appropriate color from orange to green and apply a layer of wax over the S30. I let the skis cool and then scrape and brush as always. The S30 seems to help bond the wax to the base and it enhances glide. It increases durability of the wax and the hard base resists dirt. Almost like a fluorocarbon, but there is no fluor in S30.