F1 Manager - How to choose the strategy before and during the race?

For tracks that are 6 or less laps or if the second weather condition is rain, use hard tires. For tracks that are 7+ laps and there is no rain for the second weather condition, use soft tires. You are correct that tires are OK if above 0% (unless you are almost done with the race). For sunny short tracks, it is better to use soft tires and 2 stop strategy. Depends on weather. The threshold for wet tires is +50% water but if under 50%, use soft tires if short track and hard tires for long track. Pro tip: use the green speed button at the beginning of the race and use red button after half way through race or after 1st pit stop, depending on which scenario comes first. Hope this helps!