Re: Can someone help?..tac 15 strings
You might give Jesse at ViperX Strings (216 513-1375) a call. He has made a few sets and probably could give you the specs. But I think you'll need the springs from a stock string (they are covered by heat shrink on the factory strings).
I think awhile back someone over on CBN mentioned purchasing some TAC 15 cables and a string from America's Best Bowstrings (330 893-7155).
Len and Andy here on LRH may be able to guide you in the right direction.
Hope this may help you.