Just curious as to whether or not people who do OPK’s ovulated when Glow suggest they do?

I have Glow and Flo and they have two days of difference in ovulation days. Glow tracks my cycle as 28 days per month but Flo does it based on an average which is day 27. My period usually comes anywhere between day 25-28, never later than 28 and more often than not 26.

During my fertile window we tend to have six as much as possible although usually late at night. If I’m not pregnant this month I will be starting OPK’s and I’d be grateful for any advice on when to use them?

What cycle day do you start testing? How many times a day? And when is best to have sex when you get the positive result?