Unless the stalks are weak & you do not have a fan blowing on the plants to make them stronger its highly doubtfull you'll need to stake the plants,some times its nessacary to stake but with small sized plants its very rare & usually caused by weak stalks & branches.
When to bud depends on a few different issues.
How much space do you have till you run out of room or the plants reach the lights.
What type lighting & how much total wattage are you running,if using cfl's the real world watts are the lower of the 2 figures,for example when they list a bulb as being 25 watts but it puts out the light of a 100 watt bulb its still only a 25 watt light.
How much yeild from each plant would you like to get when you harvest,remember the longer the plants veg the larger they get & the more bud they produce.
Btw,i just looked at your pics,good job so far,they are some fatties