Different lenghts of CNR b'tween left/right speak

theoretically at the transmission speed of the signal, the different lengths would be negligible. however, unless you are 100% sure that you will never want to upgrade your speaker cables, i'd go with a 16 ft pair as it will be much, much easier to resell than a single 16 ft piece and a single 8 ft. piece.

Yes there is a difference with length. Always use the same length on each channel.

Cardas Neutral Ref is one of a VERY few cables that using different lemgths will work out well, sonically. I have several customers that have done this successfully, both with high quality s/s systems and with very revealing SET (low power) systems. I would keep the ratio of 2:1 in mind for the long/short lengths and don't go shorter than that for the best sound. The above advice for the possibility of selling the cables down the road is good advice, particularly as Cardas cables are very difficult to re-terminate and almost HAVE to be done at the factory. If you are going to keep them, however, this WILL work for you..