My Pioneer always sets my Mains (M22) and Center (VP160) to large. I notice distortion at higher volume levels this way, so I always set them back to small.

I've also been volleying back and forth between a 50hz and an 80hz cross-over. Seems for some applications 50hz is better, for others, 80hz is better. The VP160 seems a little wasted unless I set the cross-over to 50hz. Although, there seems to be a more even balance and less distortion at the 80hz setting. (I can't win).