ah
ok light penetrates down a depth , this creates a potential size of plant as to go beyond this is to piss in the wind and waste growing time , a 1000w hps grows good bud at 4 foot wheres a 400w with just tickle and produce fuck all on a plant needing 4 foot of penetration ,,,,,,, so plants need to be grown to the appropriate size of the grow set-up to maximise the penetration and therefore useable light
but
root mass is super dooper important , bigger roots then more power , better absorbsion of nutes and well everything just better , a plant grown to a good hight then topped will create more bud than a plant grown to the topped hight ( if you get me )
and width , the spray of light is determined by once again the light output and also the reflector , theres also crossover light to increase the intencity on the periferies ( outside bits ) and sure as shit the reflective surfaces to be concidered
and to really piss on things as shaggy pointed out vert lights are soooooooo mucc more effective its a laugh
and strain choice , sats are desparate for light , indis arnt so
.......... bugger
ok this is about experience and trying loads of shit out ok , its not a fail safe bestist must grow type guide at all and individual choise is everything
vert hung lights in a waterfarm or aquafarm set up with hybrid plants such as cheese , chronic etc grown to 2 foot then flowered under 600 lights are IMO the very very best for yeild over light usage , every other grow style is playing catch-up in comparision be it ebb and flow to shelved verts to passive hydro to 9 foot monsters to having 500 6 inch clones under a shit load of lights , this wins everytime