Trying to determine sex

I'm trying to figure out the sex of some mystery plants I have and I'm having a hard time with it. I just started flowering them about 3 days ago. First 3 pics are one plant, second 3 are another and last three are one. Tried to get the best pics I could of the nodes on the main stalks.
 

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1 and 2 are female.
5 and 8 are male.
I can't determine the other ones.......far away shots are useless for determining sex.
The far away shots were more for separating each plants pics, plus I've heard that taller more gangly plants could be male (or sativa), that's why I included them.
 
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