I would wait until they show the first signs of being female/male destroy the males. Clone the females, THEN transplant the female(only if you absolutely HAVE to).
Reason why I wouldn't transplant into something smaller is because during the flowering phase they are very prone to stress. You have to destroy root systems to knock off excess dirt to get it into something smaller. I don't see any pictures so I couldn't tell you exactly the odd of it dying. If the plant is taller then the pot the chances of it dying are even higher(if it doesn't die it will abort making your nugs and they'll just dry up and fall off, causing your plant to reveg).
If you HAVE to transplant, I would reccomend doing it outside next to your water hose. Pull the entire root system and dirt out in one peice(very very gently), place it in the grass and gently hose down the bottom of the rootball to the size of your smaller pot. I wouldn't try breaking it up with my hands, the hose is the only way I would go about transplanting into something smaller.