You asked "what would the results of the graft be? A triple flower with a mix of the color of the scion and color of the single flower plant?" There will be no mix of colors. The graft (triple flower) will be the same as it always was, all subsequent flowers above the graft will be just like the graft. Any growth from the base below the graft will only produce the original color single petaled flowers.
The only way to get different colors is through sexual propagation.
