I personally like breeding to morphs. Because then you still get morphs if it proves to not be genetic. If its genetic, you should still be able to tell that it changed the morph.
I personally like the harlequin when it's added to mojave, mystic, or fire. Look at the pics on worldofballpythons.com and check em out. If you were worried about being able to tell if the morph contains the harlequin gene, then I would recommend breeding to a normal...