advice on SCROG Plz

I'm a rank noob so my one scrog (successful) worked where I set the screen and spread branches until the outermost ones were towards the edges of the screen. It was kind of a little bit of give and take where I was shifting and threading bud sites as evenly as I could within the scrog. Once I had that arranged I secured the screen. It worked for me since I had built a lightweight screen so even as I adjusted it, the weight of it wasn't unduly stressing other parts of the plant. As the plant continued to grow and I had to make minor adjustments, mostly for keeping bud sites in the clear for optimum lighting, I raised the screen a little bit over time but minimally - I just made sure the buds were keeping an even fill in the screen and not getting blocked by foliage. If the top of the plant is going to be 18" from the soil then if possible I would start at about 18" above the dirt for the level of the screen and possibly cheat it upwards if you have to make more vertical room to be able to thread your outermost bud sites into it. Btw - I topped and flowered first before I put it into the screen which removed the risk of the hassle I would have to deal with if the plant working into the screen turned out to be male. Another thing to consider is I decided to let the "popcorn" grow because I wanted to see how well my array of cfl lights would penetrate and having the screen as low as I did - it was a 20" plant scrogged into a screen 1' X 2' - with additional side lighting, the popcorn did fine - I think the screen spent most of its time about 18" above the dirt.