I broke down and bought the suggested yarn today in the Persephone colorway. I've been reading the reviews of the yarn on the handpaintedyarn.com site, and after much deliberation, I've come to the conclusion that the yarn isn't "bulky" in the Yarn Council sense of the word. It's sounding very much like it's more akin to an aran weight, which is just a bit heavier than worsted, so a true bulky yarn may be too much.
Hmm, then maybe 2 strands of Simply Soft would do, since it's a pretty skimpy worsted. I'll have some leftovers of three colors of SS after I finish my Christmas knitting, I'll swatch with two and three strands and see how they work.
I'll update the list when I get the yarn, but that may have been part of my problem with using Moda Dea's Tweedle Dee - well, that and the heavy duty striping, which I seriously do not need around my booty (my big ol' booty!).
I could deal with striping on the booty, it's striping on the belly I can do without.