But it is not permanent. If you really screw up you can polish it right off again. Then again, I can't imagine how anyone could screw up applying Opti-Coat.
Chris has stated time and time again, that all you need to do is strip the paint of whatever sealants/waxes are on it. How you do it and what you use to do it, is not all that important. We don't have Dawn where I am, but I gather it is a popular dish washing detergent. Any dish detergent is going to strip off what you have. A once only wash with a dish detergent is not going to have any detrimental affect on any automotive paint, be it "scary" soft as one guy put it, or otherwise. Some people do get carried away of these forums...
If you want to practice how to apply it, purchase a bottle of Opti-Seal and get your technique down pat with that. If you know how to apply Opti-Seal then you know how to apply Opti-Coat. I'd also recommend reading the "My Guide on How to Apply Opti-Coat" thread on the Optimum forum, but don't over think it, because the application is really so simple. I promise you, no other sealant is as easy to apply as Opti-Coat or Opti-Seal.
However, don't forget Opti-Coat is not for everyone.
If you enjoy playing and putting in the time with sealants and waxes then it is probably not the way to go. In my opinion, it's pretty hard to beat the look and feel of Poli-Seal, followed by Opti-Seal, followed by Optimum Car Wax on a well prepped vehicle. However, if you are a once a year polish/wax kind of guy then Opti-Coat is the answer and you have a few less products to concern yourself with. I'm sure that sounds good to a lot of people...