Yes RD, the distance of the speakers determines the required gauge. This
article and table by a veteran audio professional covers the topic.
As Andy(snippy) noted, a regular two-channel CD wouldn't play through all speakers unless the receiver had an all-channel stereo mode. With the big difference in speakers being discussed here, that might not sound too good. When you set the speakers "small" in your receiver they receive the frequencies above the selected crossover point and the sub or the "large" main speakers receive the bass frequencies below that point. I'm not especially familiar with the Bose speakers, but I understand that the cubes have little output below about 200Hz, where their bass module takes over. That's why if they're going to be used temporarily in combination with the M60s that the receiver crossover to them should be set at 150Hz or higher, assuming that the receiver has that much adjustment range.
