If you have a nitrate reading, it must mean the cycling is making good progress. All you need to do is to wait for the ammonia to disappear while you have a constant source of ammonia.
Yes, for cycled aquariums the nitrate reading is usually quite high. 40ppm is normal. Although it is best to keep it lower. I personally aim for 20ppm or lower, but 40ppm nitrate usually won't affect the fish at all.
You don't have to get Tetra Safestart unless you are in a hurry. Take your time and let the fish tank cycle the natural way will take a month or more to finish. We all have done it the old way at some point.
