question about topping

I topped my plants a few days ago. I should have done it sooner, many of them are 18 inches or taller. I didn't do it because I'm a newbie and I didn't know about it 'til now.

Thing is I'd still like to make these things bushier and reduce their height. I cut right at the top as directed HOWEVER I watched a few videos on youtube in which growers snipped several inches off the tops of their plants with several leaves on the section they cut... I'd like to reduce the height of my plants that much but I'm afraid it's cutting off a bit too much...

So does anyone have thoughts on this? How much is too much?

check out UNCLE BEN's technique somewhere in this forum. (use the search). He suggests cutting right above the 2nd true node I believe to get 2-4 main colas. If you want to keep them low as they are now, try Low Stress Training.

You certainly can top further down. I've taken a few nodes of on several occasions to control height and to beef up the main stem (trunk) in relation to the height. I haven't played with how much you can take off, but a general rule of thumb for trimming any plant is to not take more than 1/3 of its leaves off at any point, and to wait a few weeks between trimmings if you need to take more than 1/3 (though with how fast our plants grow they could grow back everything you trim in a few weeks, hehe).

I would look into LST like TommyHobby is thinking, also check out super cropping. Both techniques will shorten, and bush out your plants.