I wouldn't add a solid color.
As a pattern color there are morphs that maximize pattern. As a background color there are morphs that turn the whole snake into the background color.
But I'd add a mid tone blue. As a background color fade. Throw that with bamboo and it'd be awesome. Throw it on either super black pastel or super cinnamon and it would be amazing. Add it to pastel and it would be a lighter blue. Imagine a lesser with that color in its background, if it maintained the yellow. Awesome