Well, I would not recommend that you use one at all. There is nothing that a prong collar, or any other corrective device, can do that can't be accomplished with good consistent training and the use of a standard flat buckle collar.
Just to clarify the rules here:
Topics inappropriate on this site include:
__discussion of deliberate use of devices or practices that cause or have the potential to cause physical trauma to a dog. Boxerworld does recognise that people do have genuine questions regarding training tools (prong collars, mousetraps etc) and methods, but we support and promote wholeheartedly positive training and behavior management, that is, teaching the dog what to do by using positive methods, not teaching a dog what not to do by causing it discomfort and pain. Any threads which appear to promote "negative" training and methods will be closed.
Yes, the existance of such collars is shown in that article, but that is for illustrative purposes (no point in pretending they don't exist) - it does not imply endorsement. In short, if you want to ask questions about
why coercive devices shouldn't be used, or about better training methods, then you're welcome to do so. However, prong collars are certainly a device that works by causing discomfort and pain to the dog. As such, their use cannot be promoted on this site.
Here's a similar thread that you may find answers your questions:
http://www.boxerworld.com/forums/showthread.php?t=64158