When I do double hats, I take the easy route. I knit a hat like your yellow one. Then, using a needle one size larger with the purl side facing, I pick up a stitch in every stitch in the row above the ribbing and knit the same hat a row or two more before starting decreasing. You already know about not skimping on the ribbing. Using a crochet hook might make it easier to pick up the stitches.
It's cold here. Single knit hats aren't warm enough.
*Knit, rip*, repeat between the *s as many times as necessary.