need to know where or when to top?

Howdy, I have three plants not sure of type but the high was very nice. Very very nice, and much $$$$$ only found five seeds. Planted 10, with these five, now I have three plants, 32 " and female starting to flowering, been on 24/24 six weeks, been on 12/12 for two. another is 21" with tight BIG 11 leaves nice pistils to, starting to flowering, just figured out the flower then, but another is 28" with flowers as well, skunk smell. But each has about 15 nodes per plant, buds not tight. Lights are 4 20 watt natural sunshine, about 1 gallon pot size. But since the plants are now reaching my the top of my 4' x 3 ' box, (light moves down to 26" from bottom, then 36" to bottom) , but should i top or wait?

 

now for my next set of plants, they are 24", 10", 9", 8', 8", and six, with about five or six nodes each, so this is the time to top? and the fluor are admitting 790 lumens per bulb, which I have 4 not as hot or $$ to run, however the size of my box was wrong, its 40"x 45"x 22", light raises and lowers, to low height of 30" and max hieght of 45", so topping when they are smaller instead of bigger, these are just off 24/24 for the last four weeks, going down to 18/4.

Now question how long at 18/4 before going to 12/12, these are in 3 gallon pots, I think my mistake was two per pot, (wife said NO and was i wrong, (one per pot)
So when should I top these next plants? at what height? And at the top? Thanks