ok, this may make me seem like a dumb ass, but i'm trying to replace a pair of shoe laces on a prop pair of knee high boots for a photo shoot, and i need to find them in white. i've seriously NEVER bought just a pair of laces before and have no idea how you go about making sure you have the right size. the lace in the boots now is 136 inches tip to tip. An e-bay search yeilds no results for laces that big, nor does a google search. do you measure them in half, (68") or what?