Base wax - CH4x
Glide wax - CH4x
Fluor top coat - FC4x Cera powder.
Iron in the FC4x using a iron at 165C. After cooled, very lightly scrape. You also may make 1 or 2 light passes with the medium bronze brush if needed. FC4x is hard.
Continue brushing with the white nylon brush, then a horsehair or boars hair brush. Finish with the blue polishing brush.
With this extended period of extreme cold, the snow will be slow, 'squeeky' snow.
It is important to use the very hard CH4x wax, ironed in, scraped and brushed out well. The CH4x is even more important to use than the fluor.
A dedicated cold grind ski with numerous layers of CH4x ironed in is recommended.