Doubts about growroom design

[chicho loco]

I´ve been reading some books, pages, and stuff, but still have some basic questions, how tall should my grow box be?, I´ll use a 400w hps and sensi skunk#1.
I´d like to see a grow box design, for perpetual harvest, I can´t get accurate measures.
I know this are kind of vague questions, but approximately values are grate for me, can anyone help me? thanks.

[texas grass]

the more height you have the better if you can use the height up to the ceiling the use it, if not use as much as you can. depending on how much height you have dictates on how long to veg or to train(lst, scrog)

on a hid lighting it is good to keep at a comfortable distance from the tops of buds, put hand under light around height of the top of canopy, if its too hot for hand move the light further away