What day do you consider “first positive OPK” to start DTD?

[bluegreyeyes]

Hi All -

I’ve tracked ovulation the past 2 months.
Clean Blue Digital said “high fertility” on CD8, followed by “peak fertility” on CD9.
Wondfo strips also were dark as control line, if not darker a tiny bit darker on CD9.
Based off temping, Fertility Friend app shows also shows crosshairs on CD9.

So, my question is - do I consider CD8 "high fertility" (flashing smiley) to be my first positive OPK or do I wait until "peak fertility"?
Or should I be using Wondfos exclusively?

Thanks!