PTM - buy a used pair of each from this site to compare. Unless someone has your exact same system in the same room and more importantly your ears and taste its just a crap shoot anyways. Buying used will reduce the hit you'll take when you make your choice and flog the other pair.
Another option is to contact the Cable Co. who loan out cables for a fee.
Another option is to contact the Cable Co. who loan out cables for a fee.