What is the duration of sakta and does is it differ in the different qirah?

Question
What is the duration of sakta and does is it differ in the different qirah?

Would I be correct in saying that when the recitation is slower then the duration of sakta is slightly longer than when reciting quickly?

When doing sakta for eg on fil ardh, do i have to keep my tongue on the place where i do the laam or do I let my tongue go completely?

Answer
The timing of the sakt is less than the time of a stop in which we take a breath then return to recitation.  The application of the sakt timing it learned from reading to and being corrected by a qualified Qur'an teacher.  It is not measured in harakat. 
There is no difference in the different qira'aat as to the timing of the sakt.

Yes, when you are reciting slowly, the sakt will be longer than when reading quickly. 

You would keep your tongue at the laam saakinah when making a sakt on for the duration of the sakt.