Need some help, i m on my 4th week from seedling.

This is my first grow, i m kind of doing good so far from what i see n learn from reading a lot online. my plants are about 14 inches tall, i wanted to know for how long i have to vegg... because i dont want them to get really big in the end of process. i m looking to get them about 5 feet tall. and now i m using Cfl for vegg, and for flowerng i m goin to use 400W hps (1).

I'm no expert, but I've read that during flowering the plant can grow two to three times its size at the time you make the flip depending on the strain. If that's true, you could probably let it reach anywhere between 18 to 24 inches before the flip given 60 inches is your target height. Good luck.