Wait for More calyxes open?

Difficult to say, but judging by the stigmas, I'd probably say another week or two.

She looks awesome man, well done!! I'd say check the trichomes. If they are about 20% amber then I would start the harvest., otherwise you may only need to wait a week or so. If you are flushing i would start now but there is no real need to flush, the cure will sort all that out and by flushing you are stripping nutrients it needs to ripen buds. I hope this helps, good luck and happy growing