I am in week 3, and i Do not want my plants to get verybig. i would like to iether bud them @ 3 feet, or have them b 3 or so feet at the end. does this sound good? should i veg for 2 months then harvest? is 60 days a good veg time?
You can put them on 12/12 any time you want. The earlier, the shorter the plant will be. They won't actually start flowering until they're mature...but the decreased light will keep them from growing as big as they would otherwise.
If you only want the final plant to be 3 feet tall, 60 days veg is probably a lot of overkill. The specifics depend a lot on what strain you are working with, but in general, you can figure that a plant is going to more or less double in size between the time you start flowering and the time it's finished.