Issue 24 of The Wheel has a lovely article by Libby Kingscote about mixing colours. She uses Ashford's merino / silk mix in vanilla (pure white undyed) and one of her recipes is for a teal. Spun very fine, this would be perfect for my Twinkle. More about the spinning here.
I made a slightly bluer mix - 3 parts blue to one part yellow.
The variegation that you can see in the last picture is a happy accident. When I first popped the skeins in the dye I forgot to untwist them. I untwisted them but the paler patches remain.