Speaker cable length

@simao I believe you are approaching this the right way. You purchased a quality speaker cable (inexpensive as well) and have positioned yourself to try both system arrangements. I predict you will like the soundstage benefit the rack by your side arrangement will provide. 

@mesch thanks. I'll post before and after pictures on my virtual systems page when my amp gets back from being serviced.

Looking forward for your thoughts and pictures.

 With low output impedance ss amps and the typical heavy gauge speaker cables used today, the length is less critical than years ago when high output tube amps and thin gauge zip cord were used exclusively in yesteryear.
 Reasonable differing distances with most speaker cable won't affect time very much, but depending on the cables used might load the amps channels differently.
 Perhaps the best reason to buy identical lengths of speaker cable is to facilitate resale value.
 FWIW, I always use identical lengths.