Should I top these now or wait a while?

I have never topped or fimmed a plant before. This is my second grow under cfls, and want to try these techniques. These two plants I was going to top. They are a little over a month old, about 4" high, and have 4/5 sets of true leaves. I am a little nervous about killing my ladies...any advice regarding where I should top, and if I should wait awhile? Thanks for your help! Especially should I wait for the next new growth to appear before I start topping?

top now im 30 or more days in and just did it. mines a 200watt cfl microgrow. when she flowers shell double or triple in size givin the right conditions. But topping early is good.. 2-3 weeks before flowering so it has time to recover.. and at the most 1 week into flowering could be accepted just add another 10-15 days to your total harvest. Hope this helps i know this site has alot to offer.. Also read The Cannabis Grow Bibles..

also im not sure how nuub you are but from one to another those cfls can get within milimeters of the plant.. and thats important for good cola... i use betweem 100-200watts of 26 and 42 watters and each bulb is movable just enough for great placement.. fulll coverage 12/12.. this means the light can be more focused to your colas or your entire plant.. the closer the better.. but a leaf can burn if left TOUCHING the bulb for a few hours..

thanks dude... ikeep the bulbs around 2 inches away because I have had some temp issues trying to get my second grow going. I got 14 26w in a closet without great airflow, so I found keeping them a little further away helps. Is there any way to mess a topping a kill the plant or is it pretty safe to do? As far as I could tell there are only pro's to topping, haven't really found any cons.