making the photoperiod switch?

I have 1 violator kush, 1 white berry, & 1 ak-48 @ 3 weeks veg. They are all about 12" tall and I just started the dark period this morn... Has anyone noticed a difference between 24 hrs & 36 hrs dark to induce flower? These are all femmed so I should be good on sexing, fingers crossed. What experience should I expect to have from this time on [flowering] with these strains? And finally, can I go all the way through the grow without a carbon filter? I am willing to spend a ton on ONA if necessary, just need to keep smell contained in a 8' X 4' closet..

I had 4 lemon skunks with a homemade carbon filter and that didnt no do the job to say the least...Weed is stinky..You could smell it walking up to my house..So I think you will need a carbon filter if you dont want everybody knowing..You should expect hairs in about a week and then very slow growth until you reach 5-7 weeks then they will fill in nicely more each day..Stretching might be a problem for the next couple of weeks but once they stop stretching the bud will pack on..Good luck