I think g/m2 is a better guide of how efficient your plants are at filling the space .. anything over 400g m/2 is a good use of space
g/m3 would be even better, but i do not think growers have evolved that far yet, maybe some of the vertical growers lol
when folk grow SOG or use lots of small plants to fill a large space, many of these growers fail to account for the extra mother space they require to keep all those cuttings coming constantly
if you are using 50 sog plants to fill a space you could fill with 8 large plants .. 8 large plants would only require 1 tiny mother for the clones , virtually no space at all devoted to mothers
50 healthy clones for sog would require a few healthy mothers in a much larger devoted mother space
this extra mother/veg space also needs to be accounted for when working out how efficient smaller faster plant growing is
peace