First Indoor Grow Plan

Hey all, im new around here. Was on overgrow back in the day. Heres my plan so far.

http://www.htgsupply.com/viewproduct.asp?productID=50815

I will use this as a medium though.
60% potting soil
15% perlite
10% masonry sand
10% worm castings
5% pre mix npk=12/6/6

Will keep an oscilating fan + humidifer in the room as well.

nutes
Fox farms Grow Big for veg, and Tiger bloom for flowering
My questions are ventilation... Do i run lines to take the air out from around the plants and into the attic, and run lines pushing air towards them?
How long should I leave in 24-0?
Im using feminized seeds, so should I sex them anyways? If so how many weeks do I wait to sex them?
I will then switch to 18-6 for veg.
Im sure I will have other questions but until then.
-sway

What's the dimencions of ur grow room? And truefully u can leave ur 24 hr cycle as long as u want. me I want a shit load of bud so I have 4 of of kush plants that I vegged for 4 months there huge and I just started flowering them. On the other hand I have seen ppl start flowering as soon as 17 days in veg it really comes down to how much bud u want and how much space u have in my room I have 2 computer fans that really move the air around and I open it up regularly to keep good ventilation going and ur soil and nuts. Sounds good but I'm no expert on this though

Im gonna be using the spare bedroom of my house... so its pretty fucking big... Heres an update of the materials im gonna use, i found a hydro store in town

So i checked out the local hydro store in town I never knew existed and here is what I will be using.

Medium:
Fox Farms Ocean Soil

Nutes all FF
big bloom, tiger bloom, grow big
viagrow ph +-

Lighting
sunlight supply 1000 watt system
plant max 1000 watt MH Bulb 110,000 lumens
plant max 1000 watt HPS Bulb 140,000 Lumens
sunlight supply yield master II classsic 4ft Air Cooled
Viagrow 26' light hanger

I want to grow Greenhouse Lemon Haze, PPP, and White Widow.