You can expect 400g out of a 400watt light if all is FLAWLESS.
Chances are, 100g is most you would see.

Don't be fooled by maturing hairs, you can't judge a plants maturity by this alone.

Get a good magnify glass(radio shack has a good one 100X for $10) and check crystals
Clear=not mature
Milky=maturing
Amber=almost ready to explode

Harvest no earlier then half milky, but u can let them go until half are amber.