S.K.
I read your update so I'm sure everyone is different, but we (my husband and I) personally have this one figured out. Without providing TMI, if we TTC the day following the most clear, stretchy cervical mucous, we are pregnant (has happened 4 times now!). I would wait at least 3-5 days after seeing it to prevent pregnancy. On the front side, we were TTC for 13 mos. on the day of the mucous to no avail. So for us, it's always the period of time following it. Stay safe!