Zebra strings are made out of Fast Flight... the material that everyone used back in the 90s... it's know for it's ability to strecth further than a rubber band...

Barracuda strings are made from 8125.. which is a much better material than fastflight.. Winners Choice strings are also made from 8125... WC just does a better job w/ stretching them in and serving them very tightly.

I would take the bow back to the shop and they should reserve the center serving for your. It's not that big of a deal.

If you want custom strings definately check out Vapor Trail... about 1/2 the cost of WC and just as good. Vaportrail also makes the stock strings for Bowtech... who has the best stock strings of any bow out there.