2. Once 3 or 4 days after you start
3. Sort of, there is a guess, here is what Richard320 took a swag at here, Extended OTO color comparator?
Blinding yellow is about 10. School bus yellow is about 12-13. Hunter orange is around 18, up around 25 it starts to look pumpkin orange. I never went any higher than that, but it's been reliably reported that it eventually will turn brown if you get high enough.