Yes, most common cause of Sciatica is a slipped disc. This is where soft tissue between your vertebrae pushes on the Sciatic nerve. Using the Flexi decompression of the spine will allow the tissue to slip back into place and relieve the pressure on your Sciatic nerve.
Depending on your condition you should use the Flexi everyday whilst in pain. once symptoms clear you can drop to once or twice a week.
5-10 minutes is ideal depending on your comfort level.
No, its recommended you start on the first setting and move your way up as you get familiar with the product. you will realise from your comfort level when its time to move up. Remember, walk before you can run.