Cycling a tank for weeks is a thing of the past. Cycle and stability, are great products that boost the biological filter and work great if you don't kill them (with a UV filter for example) since they are water borne. Eco is an excellent substrate, and comes with living bacteria on it. Plants also aid in cycling because they use up ammonia, nitrite, and nitrate. I cycled a 125Gal tank for 3 days before putting in fish, and had no problems at all. Don't be fooled though, putting in too many fish at once at any time can result in problems. In one week you can have the aquarium completely setup if you're careful and work hard.
You cannot overdose Cycle or Stability or any of those other products. I think what Styxx1 meant was that you had to dose as often and as much as they tell you, and not any less. This is NOT TRUE and is simply the company's way of getting you to use more of their product. Once your bio filter is setup and your tank is completely finished, you should have no variations in the nitrogen cycle. That means adding extra bacteria will be wasteful. It is at times like adding new fish, or in broad terms, new stress on the bio filter, that you need to add bacteria.