Timing suggestions

Just looking for some input on timing…I have 2 strains currently in flower:

Gold Leaf - Flower time 9 weeks
Super Silver Haze - Flower time 9 weeks

Both plants went into flower on 5/18/2020.

I know there is a stretch period for a couple of weeks that I do not believe count…so if I am doing my math correctly…Their flower time starts on 6/1/2020 correct?

So approximately 9 weeks from then is when I should start checking to see if they are ready?

I know every plant is different, but just looking for a general timeline…

General timeline, you buffer 2 weeks into transition to flower, then after that you would count “flowering times”.
Hope that helps.