um, well starting seeds and going to 12/12 immediately wont just put it into flowering immediately I dont think, it has to have some infrastructure or else there is nothing to flower.
what you're seeking, given your two week cycle desire, is to make a separate space and create a mother plant. you'll identify a female, and grow her up in constant 18/6 light (or 24 hours), never let it flower, and keep taking clones every two weeks.
I guess it works like this, you start a few seeds, when they are of decent size to take a clone from, you do so. actually I think you can just stick it in a glass of water and put it into 12/12, you'll see the sex of the clones, and will be able to identify if the plant it came from is male or female.
then you take the female plant and put it into long day light vegetative growth. give it veg nutes, sing it veg songs, etc.
when it is big enough, take enough clones to harvest as many plants as you plan to.
start flowering them
then when those are in flowering, figure out when they'll finish, and have clones ready to go in when those are done.
when the second round of clones is two weeks from harvest, take another batch of clones and root them, then when the 2nd batch comes out they are ready to go in, etc etc.
of course you'll have to figure out the exact timing, depending on flower time, time to establish clones, whether you want them to veg at all before flower, etc.
good luck