i have never heard of 8 on 16 off for growth. the other way around, yea.
but photosynthesis is a light dependent reaction (of course). which means the actual process of turning gases into sugars and creating energy for growth begins on a full scale after the light has been on for a while (not to long of course)
there is logic to that fer sure. however it isnt anything to do with growth that is for sure.
thc levels drop in the day and replinish in the night. it would definetely make perfect since to have your light off 16 hours the day before you harvest- simply because it would prolong the descent of thc levels, and probably/possibly raise them a tad, tad bit more.
but it most definetely has little to nothing to do with growth, and i would suggest if you plan on doing that, to not do it more than a couple days.
11/13 has been around for a while- to me there is little difference. some people like it some dont; and i think it mostly affects early bird strains (fast flowering strains) more than anything.
but there should be no 'going back' to 8 on 16 off. if you are to use that, you would definetely only want to do it for a short amount of time before harvest- not at any other time during the life cycle.
also, it is pretty concrete that harvesting by the colors of the hairs has many flaws, and isnt very accurate. certain strains will have pistils and pistil production that act differently- not only that but individual plants.
in my experiences most plants will shed plenty of hairs and replace them with new white ones a cool second before harvest. leaving you with a scattered amount of amber hairs for a couple weeks.
some strains and phenos will have pistils that hardly red at all, and spend excess energy in keeping them hydrated- as well as diverting more thc to the trichs which can all lead to the hairs staying mostly white- while the trichs may tell a different story of optimum thc production.
it is best IMO to harvest by the look of the trichomes and not the hairs. unless you know your strain, you know the general flowering time, and know your getting close, i would leave it until trichs have shown the plants peak thc output.
alot of inner calyxs will burst the last week or 2 of flowering, putting on well needed girth faster than the previous weeks, usually.
so you dont want to harvest early. not only will you pass up higher thc and cbd levels, but you can pass up weight that of course you want.
also, unless you bought those nutes in the netherlands, the scales will be a generalization, and not completely conduscive (sp?) with mj growing. not a huge difference either, just stay at 1/14, and maybe flush a little before harvest.
like papa said, he only flushes a little and keeps it on 12/12 the whole time. there isnt really a right and wrong way at all, concering most everything on here.
it is just style,technique, preference, and what one ends up being comfortable with. but in the end there isnt much hard evidence to prove any superior; because there is so much variety out there in strain, pheno and setup; ya know what i mean?