Since you are watering twice a week, and since Rain skip is looking at -24h and +24h (2 days), you can up it to 0.25in if Rachio is predicting actual rain correctly, or be conservative and use 0.5in. Saturation skip will also look at soil moisture and skip watering if all zones will have enough water till next watering cycle. Also monitor it the next time it rains to see how it is working out. I usually look at cocorahs.org for the daily precipitation as well as Personal Weather Stations in wunderground.com. I use Flex Daily and watering any day, so there is room for error because if it doesn’t need to wait 3 or 4 days to water in case it skips watering one day and predictions didn’t actualize.
For the irrigation precipitation rate, I would recommend doing a test, because the test will capture actual precipitation as well as efficiency. Rachio default for rotors is 1in/hour but mine was putting down 0.3in/hour. That’s a big difference.