You have a large gap between 3 & 4 jumping from a light to a dark. I agree with the two very lights. 15-17, you may depending on the final size of the bargello rectangle, the colors might become muddy because of the numerous colors. 21 also has a lot of what appears to be grayish tones. I have mostly worked with the smaller segments (1" x 0.5"") of Eileen's quilts. Before you cut, you may want to sew a test strip and either take a picture changing the colors to black & white or scan the fabric in black & white color mode. Good Luck!!!