vert lighting

Posted this in the vert sec and got no love or im impatient..

Okay the general consensus for horizontal is:
400 = 3x3
600 = 4x4
1000 = 5x5

Personally i don really agree but thats aside the point. Im wondering how these numbers translate in a vertical donut.

Sir KK

Calculate area of the cylinder and attain desired watts per sq ft.

Bah im still confused.
A 4ft high 4ft across cylinder wud need 2500w to be 50w per sq. I aint puttin 2500w 2ft away from the screen.
So either vert is viciously under powered or it doesnt require as high of watts per sq as traditional horizontal. Im assuming the latter.

Sir KK