use the same color thread top and bottom, it makes the back interesting as well. I would stipple the alligator in green. and a larger design in the the stripes but use matching thread for each. White in the white, navy/black in the dark. (can't tell what color it is) You could use one color or the other if you choose to do a design that goes all over and into the stripes. Not sure what type of larger design I would suggest as I am still thinking about that as well. good luck.