I'll take stab at it.

All I can offer is personal experience, but I have grown some large, tight buds in a 2' X 2' area with 56 Watts of 660 nm. and 460 nm. Ledengin emitters with a ratio of 4:1.

About $170 worth of parts for the "cake-pan" light.

'bout $250 for the 150 Watt "Frankenlight".

There's pics in my albums.

Course now I'm seeing UFO knock offs on da bay for $150 w/shipping.
But, dunno how well they grow.
I was impressed with what my homebrewed light produced.
Rivaled their outdoor twins. :thumbsup:

Aloha
an a ha'penny,

Weezard