c903 good point, and one that should not be forgotten.

Here is my advice, go with the custom string from your dealer, it will be much better then any string in a box because it will be served exactly to fit your bow, however, know and ask questions to your dealer about the pros and cons of each string material, you may want a material that meets your needs better. There is no one material that is perfect. Also ask him about the number of strands that he is going to use in making the string and what are the benefits with going with a few extra strands. Here is a site that will provide you with a little information on the types of string material out there and how they perform.

http://www.webspinnerz.co.za/bowstrings/