2nd grow stealth

hey,
as a curious fellow smoker/grower i was after some answers and thought rollitup would be the best place. let me tell you a bit about my set up..

i currently have 2 anonymous strain females under a 400W hps. ventilation- a 400cm oscilating fan on medium creating steady air flow and a 150cm carbon sok for extracting air and replacing it. my 6x5x6 stealth room is lined with mylar and temperature sits around 75-80. they started showing their pistils a few days ago. my plants sit on a heat pad which gives the roots xtra warmth. they sit approx 1 foot away from the bulb comfortably without getting burned. 1 plant is 500cm tall and the other 450cm. they are 6 weeks old today. nutes- growzilla for vegative growth, budzilla for flowering and superthrive. pH level is at 6.5. my lighting hours are 20/4. atm im feeding them 500ml of required solution every 2nd day.

could someone plz tell when abouts i should start flowering.
im going away for new years and was wondering if i could complete the flowering stage b4 the 27th of dec including a week or two 2 dry.
thanks heaps!!!

If their clones start flowering at 18inches,If their from seed start when they reach 2ft. tall.They better be mostly indica.indicas take 6-8weeks to finish budding.

sweet thanx 4 your comments. appriciate it!