I would leave it a single color. I have painted several bikes with a rattle can and the only one I didn't like went very sour when I tried to add a contrasting color head tube. That bike had Nervex lugs though & yours would be easier to do a good job on the masking. Be sure to give the paint lots of cure time to harden up. I found my paint jobs to be pretty brittle & they chipped up as I rode them.