This is a great blend of an interesting shape with an interesting stitch pattern and truly, an interesting yarn. The Cottonsoft Candy has a heaviness to it which will keep those side opening fronts from riding up and the speckles don't overwhelm the intricate lace pattern. It's a great combo.
The pattern is written for the Cottonsoft Candy which is interchangeable with the Cottonsoft DK and and the Cottonsoft Crush and Baby Crush but I'm also going to recommend the Drifter Subtle DK which is still a bit cottony but also warmer because of the wool and acrylic content (especially note that stunning Mustard colourway!).
You will need 3.75mm and 4mm needles.