First Timer W/ Great Ideas

hey everyone, Im def. not new to the marijuana thing but new to the grow. I just have a few questions and I will be on my merry way to happiness. I have 1 1000w hps and a lot of space to use it in. what I would really like to know is: If i were going to top the girls off, how many girls can I put under that 1 lamp? How much space can it be done in? (I want to get as much out of this as I possibly can) and also when should I top them? and after topping when can they go to flowering? any help would be awesome, try to be specific on this, please!

you dont need to top them if you have room, topping just promotes growth differently. if you have all that room and an HPS you do not need to top your plants. you can fit more under the light if you dont, because they will grow more up instead of out.