For those of you who chart & keep track of CM, how many days before O do you notice the first EWCM?

We are not TTC, but I am trying to line my O date up with my online period tracker. I will temp once we're TTC, but for now, I'm just curious what the average is.

Also, I'm right on track to start my period the day we take a 5 hour plane trip, which is just fucking fantastic. If there is a magical way to speed up AF or delay it, please tell me. I seriously considered getting pregnant so I wouldn't have a period on vacation.