Advice welcome, newbie growing Blue Cheese.

Hi all, I'm 2 weeks into the flowering stage of my first grow and would be really gratefull to recieve any advice or feed back on my current setup, which is as follows:

Grow room is 1m * 1m * 1.7m high. The grow is inside a closet in a spare room and it vents into the attic space, i pull cooler ambient air in from the other side of the attic using ducting.

Maxibright 400 watt ballast with 400w sodium bulb.

Metaglo mylar sheeting.

150mm inline fan (exhaust).

6"Clip on fan (ventalation).

2-4' Chains w/ S hooks.

2*Grasslin segmental timers.

Thermometer & Humidity dial.

Terra Professional Soil.

5 Litre standard round pots.

Canna Terra Flores.

Seeds: Blue Cheese Barneys Farm (Feminized).

I've inherited this grow so to speak; a friend tried himself and failed producing approx 6 ounces from 6 plants, all were grown in normal garden centre compost and each plants was nearly 1.2m tall, using a 250w sodium bulb and feeding his plants baby-bio during the both the vegative & flowering stage!!! Luckily, a healthy plant was taken during the vegetive stage and placed in another closet under a 250w blue crl bulb. 9 cuttings from this mother have been successfully vegetated for a total of 4 weeks and since then they have been thriving in the above mentioned room for 2 and a half weeks on a 12/12 cycle. They currently stand 2 feet tall, with buds forming rapidly, crystals are already abundant forming on both the leaves and the buds. Every 3rd day each plant gets 5ml per litre of canna flores nutes added. The plants are kept a minimum of 8" away from the lamp and the room temp is a consistant 27oC and 50% humidity during lights on. I'm thinking of starting to use some pk 13/14 also? Any feedback or advice on the above would be warmly accepted.

Thanks alot people.