Just before the end of pre flower.
Them buds that you've pointed out. May aswel be left. As they've used up the energy now. So, may aswel let them all ride into the harvest together.
Its all about energy management in fattening. And pre fower is where the stigmata starts giving you those buds (pointed out) they need to go before or just coming into fattening
(You'll know when the plant stops stretching upwards, its finishing pre flower)