Forecast/Conditions: Friday night low of 1F, racetime temps below 10F. Chance of snow Friday night and Saturday am during the race. Winds 5-10mph. Mostly cloudy skies, 50% chance of snow.
Base: LF10 Green or MF10 Green, scraped while base is still warm.
Glide: HF10 Green, scraped while base is still warm. Brush with fine steel or copper brush, followed by horsehair, then hard nylon brush.
Top: SFR92/HF13 block might improve glide, but with new snow in cold temps like this, factoring in the breeze, the HF10 Green alone would be a safe bet if you don't have a chance to test the fluor overlay. If you have an extra pair of skis, apply the fluor to one ski, go skiing, and do a feel test against the other ski to see if which ski is more free underfoot. It can be risky to apply too much fluor in cold, drier snow conditions.