veg to flower transition q's (first successful grow please help)

Hello all, I am currently trying to journal my first successful grow, and been doing alot of reading to make sure i dont up but I still am not sure exactly when and how to start the flowering process. I am growing 3 fem AK48; 3 fem wonder woman; and 1 full moon. I started Germ on sept 24 and put them in my cabinet CFL bubbleponics setup the 27th so they are almost a month old. I am using general hydroponics grow and bloom nutes at 2200ppm and ph of 5.5-6 water temp between 73 and 75 F and exchange a gallon a week (out of 4 gal res.) For light 15 6500k 100w equiv. CFL's 24 hours. And I have only 30" max height available. the plants measure between 3 and 4" currently and have an average or 4-5 main colas.
So, my questions are as follows:
1)how tall/when should I start flowering so they dont grow past 30"
2)how gradually do I change the nutes from veg to bloom
3)when should I think about cutting clones

any help would be great, thanks.

1) Depending on strain is how much a plant will grow when put into flower, mostly I find that they will up to double in size. I have heard of others talk of their plants more than doubling in size but I have not experienced this.

2) Just change the nutes. 1st week of flower keep using veg nutes, 2nd week flower start on flower nutes, it takes a while for the plant to turn to flowering mode. If you use and addative to kick start the flowering process such as 'Bud blood' then I wouldnt bother continuing the veg nutes for the first week of flowering and just switch straight to the flowering nutes instead.

3) You can take cuttings from any healthy well developed plant, from the look of your babies they are def good for cuttings, rule of thumb to remember when taking cuttings is to never cut more than 20% off.

Your ladies will grow 2 to 3x their height once in flower, so if you're limited to 30", then I wouldn't allow them to go over 10" before flowering. I would take your clones right before you out them into flower. For the nutes, I'd give them about a week into flower before changing their nutes over.
Good luck!