Speaker cable vs. interconnect cable length

Go with short speaker cables and long interconnects.

Just get decent cables. I wouldn't worry so much about interconnect length. In my experience, a 3ft IC will be noticeably better than one that is 20ft. But it's not like the sound deteriorated into something unbearable. In fact, you'll probably lose a bit of dynamics and sound a bit rolled off "in comparison" that's all.