I just learned that OPK can detect LH surge at different times of the day (might detect at 2pm but not at 6am), and that once it is detected you should BD because you have 12-24 hours. Has anyone detected a surge many hours (12+) prior to BD? For instance, you tested positive first thing in the morning, but don't get around to BD until 9pm that night but still got pregnant?

Hubby and I work off schedules (him 2am - 4pm, and me 8am-5pm), and the window of ferric pregnant is so small already, I don't want to miss out on the golden opportunity!