first time grower

Ok im a first time grower looking for some advice. I purchased some northern lights online which i plan to get going soon. IM planning on flowering 4 females at a time.

My veg and flower rooms are both 4x4.
Veg room will have an exhaust and intake and probably run a small fan inside to move some air around.
Flower room will have an exhaust fan on the top and a larger intake on the bottom.
I plan to use flouro tubes (cool white) on the seedling until they are a few inches and then put them under about 8 cfls (6500k around 30w) and veg them for 6 weeks at 18-6, then flower under a 400w hps 12-12 for 8 weeks.

Ill be using good organic store bought soil, with some peat moss sand and pearlite mixed in. Starting in cups then going to larger pots with rock in the bottom for drainage. Im planning on using a 20-20-20 fert while vegging and then switching to a 10-30-10 during flowering. Planning on starting ferts a week or so after i repot and put them under the cfls at 1/4 strength then increasing over time.
Im hoping to yield 1oz dry weight per plant. I dont plan on using any grow method on this first run just gonna let them reach to the sky.

My main concerns are what size exhaust fan would be suffecient for the 400w hps and are the nutes correct, and when do i switch to the flowering nutes and when do i stop the nutes. Any other advice would be greatly appreciated. Thanks buds.

oh, and i have both boxes lined with mylar also if that makes a difference

first you should always start your plants off in the same size pots you plan to harvest your plants in. transplanting too many times can cause unecessary stress on the plants resulting in hermy-ing the plants. the rock in the bottom of your pots will be superb for drainage! thats what i do.. layer of soil in the bottom then a layer of rocks then i finish the rest of the pot up with soil, sphagnum moss and perlite. the time to give your plants the nutes which contain more Phosphate and Potassium are the nutes you want to feed the girls when they are already in the flowering cycle! Nitrogen promotes vigirous stem, branch and leave development, Phosphate promotes strong, healthy root system development and Potassium encourages big, dense flower(bud) development. Dont worry about micro-nutrients as much unless you come across a defficiency or toxicity issue! for exhaust and ventilation i would cut a decent size hole at the bottom of your grow box with a oscilating fan to bring in air and cut a hole at the top of your grow box(because hot air rises) with a stationary floor fan to push the air out. you may have to build a little shelf to place the upper out-take fan on. hope that helps

the mylar makes a huge difference! r u using timers for your lighting system? if not make sure to since you wont always be home to switch the lights from on to off and vice-versa! another thing to keep in your grow area is a thermometer, hygrometer and a moisture wand.

yeah, i just planned on repotting them once when they reached a few inches to their full pots, then waiting a weeks or so to start nutes and yeah ill have both rooms on timers, and have temp and humitity under control, as well as keeping ph balanced

so i need an exhaust fan for the veg room or will an exhaust and intake hole with a fan near the intake be ok?
and does the exhaust fan on the 400w hps need to be constant, or can i put it on the same circuit as the lights?

and are those ferts ok? 20-20-20 veg and 10-30-10 for flowering