the amount of stretch is dependent on so many things its really hard to say.
pics, strain, and grow method would help a lot.
ex. I am on my 3rd round with the same SLH plant and its stretch has been different every time, depending on the veg time i give and the number of tops i allow. different methods have resulted in any where from the nearly tripling in height on a 14" plant to only increasing about 10-16" in on a 4 foot plant. (experimenting to get the time/quality/yield ratios ideal)
the best method i have found to control stretch is adding more tops, however i expect it may also lead to smaller less ideal buds, but we will see. I am feeding it nutes mixed at 1.5x strength on my 4th week of 12/12 and there is no sign of even the smallest amount of nute burn. I haven't decided if it's a good or bad thing.