Depends on what type of ski you are going to use or have on hand...waxless or waxable. Waxable is best for a smitty, of course. Just make sure the weight of the sled doesn't compress the ski scale kick zone into the snow...(on waxless) That can be avoided by using longest ski you can find...210 or 215 cms. Even the waxless can use wax or the wipe-on teflon coatings on the glide portions. As a former long-time XC skier, make sure you use the right type of GLIDE wax, or get some Maxiglide or the new Teflon coatings you can put on. Lots easier than wax, and works well. Make sure to scrape bases smooth, and fill any gouges in with a stick of Ptex before you layer a base. Just my .02.