400w MH / HPS Grow ....... noob Going Pro ..... i need your help

Ok ... So I am attempting my first Professional light set up .... I will be using

-400w HPS / MH Lights
-400w MH / MH Ballest
-Batwing Reflector
- Miracle GrowPotting Soil
- 5 bag seeds
- 5 blue mystic autos femonized seeds


Please leave feed back n pointers

.

- what size space
- what are your plans for ventilation
- are you familiar with water pH
- how long will you veg for
- are you planting all seeds at once
- you know MG has nutrients, so you won't give nutes for at least the first 3 weeks to a month, right

Happy growing

-spek