I was able to create this lovely speckled Kikyo by crossing Kikyo Ten Ten with a Double Kikyo and grow the F1 which was a solid color. Then I collected all the seeds from the F1 vine and selected for the speckled flowers seen in this gallery.
Thankfully, the Confetti Mix produces plenty of pollen so that most of the vines are a product of self-pollination and the appearance of the vine will conform to the expected appearances.

Japanese Morning Glory Blue Speckled Kikyo Confetti Mix
Japanese Morning Glory Speckled Kikyo Gallery
confetti mix A Lake Mary Gardens