Is using commercially available yeast to create a sourdough starter effective?
Don't do this. A sourdough starter contains several strains of yeast and bacteria in a fairly delicate balance. These consume sugars and produce CO2 and a range of byproducts. Commercial yeast is a different species of yeast, engineered to eat and reproduce much faster than any of the wild yeasts in your starter. Adding commercial  yeast to a starter will lead to the commercial yeast outperforming the wild yeasts and gradually replacing them. You will end up with a commercial yeast culture, rather than a sourdough culture.

Edit I realise I have somewhat misunderstood your question. The answer still holds, though: you cannot start with commercial yeast and expect to create a sourdough starter. The commercial yeast would prevent any wild yeasts and bacteria from colonising the starter. You can keep a culture of wild yeast (to some extent), but as @Chris H's comment states, it won't be sourdough.

If you want a better guarantee of success, your best bet is to somehow obtain an offshoot of someone else's starter. Some bakeries will be happy to give/sell you some, or you can try buying a starter online.