I have just made the one black and white print string quilt with the yellow centers, but have more planned. It Depends upon the look you want, but I probably would not mix cotton prints with batiks unless the colors were in the same hues. I also think contrasting color values play a pretty important role in the overall look of a string quilt. I alternated black background strips with white background strips. So think about that (alternating light and dark strips) or putting all darks on one side and all lights on the other gives a whole different dimension to the overall quilt. I know some can be happy doing the "grab bag" approach, I just can't bring myself to do it!!! I am currently working on a modern wonky log cabin in bright colors and find myself choosing each color strip individually as I build the block taking into account the other colors in each block. I guess I am just too controlling to be able to go truly random. Oh and I do think you should cut more color strips to have a good cross spectrum unless you have a specific color theme in mind.