When I make a scrappy quilt, I don't pay much attention to anything other than value. I use batiks and prints and solids and mix them all together. Many of the fabrics clash with each other, and often clashing fabrics are right beside each other. However, there are probably at least 100 fabrics in each quilt, each one is only 1" wide, and I think they all play well together. I never seem to have enough light fabrics, so a medium fabric may get mixed in where the lights should be. The same medium may get mixed in with the darks in another block. So I'm probably breaking all your rules - but I like to use up my scraps. I wouldn't buy all these fabrics for the purpose of putting them together, but hey, scrappy is scrappy! If your friend's quilts really look bad, she just isn't cutting the fabrics into small enough pieces. ;-)