Forecast has temp at 10F for start. Those in the long race may have an advantage with FC4X fluro.
It is very important to iron in a couple layers of CH4X wax to harden the base for the very cold abrasive conditons. A ski with the least amount of structure is highly recommended.
Note: You must use a very hot iron (150C or 320F) to properly melt and iron in CH4X. It takes more passes (7-10) of the iron to heat up the ski base and melt in the very hard CH4X wax. There should be about 1-2" of molten wax trailing the back edge of your iron.