You can't base wether a plant is a keeper or not via a single run... I treat seed runs as only a preview... yield, potency, everything (most times) evolves and gets better with maturity... it's genetic drift caused by us when we toss a strain in the corner of the far side of the veg room for 3 months in a 1 gallon pot or whatever and then expect it to perform like a champ when we pull a clone or 20 to grow and end up with herms and shit on top of less than perfect representation of what we had... I don't believe in genetic drift based on what a plant does the older it gets but you can usually trace back a bad run if you let the plant grow like shit for any period of time without regrowing the plant to perfection and then taking clones to be flowered...
That and I've never seen the true potential of any non-feminized strain the first go round from seed (nor feminized honestly because we get better at knowing the strain usually as well)... it always takes a run of clones to see what you really have as far as overall keeper-ness and finish time... usually time posted by the breeders are obviously best case scenarios but I will say when grown right (meaning no fuck ups feed wise, green top to bottom beginning to end...., or major stress instances) from clone to harvest, 99.5% of my strains land squarely within the posted time frame unless I get a hard leaning pheno that's more like one of the parents than the intended cross but obviously that's expected... also grow method will effect flowering time... I have a cheesequake pheno that has been a 65-70 strain from the first time I flowered her clones in soil until the last time I flowered her in soil.... then I ran her in a hempy grow and it was so unbelievable that these plants were done as I've had this pheno for years now, could possibly be done.... by the time I decided it was even reasonable to use a bud scope, it was over ripe... now I just ran her in my first hydro run and she finished proper in less than 8 weeks... and I also count from the day I drop the plant in the 12/12 room and the lights go through a complete on off cycle as day 1 of flower... if your plant is mature enough as they usually do when you keep mothers in perpetual veg for long periods of time between making a new mother; they can't wait to trigger it seems...
On the subject of changing from the standard 12/12 flowering frame to whatever #'s work for you, I tried all the mentioned combos but other than trying to save on your electric bill I can't find any reason to deviate ever again... as far as dj short...I was pretty sure he was talking about something with breeding... that's vague and something a person who just ate 3 deadly gummi bears about an hour ago would say, but I'm almost positive he was referring to looking for a certain male attribute by changing the hours but I could be wholeheartedly wrong and gladly admit it... but if you (whoever posted that) actually spoke to him on the subject as well as others I guess I was imagining it but I was almost certain it was about finding something in a breeding male and he wouldn't give up the exact time frame he insinuated it was somewhere within an hour off of 12/12... which way??? I can't remember actual details now....lol... but I'm pretty sure it's in his book... maybe I'm high n should shut the fuck up...