There's been little progress to report, but here it is.

I got about 13 inches into the back of the Helena Jacket before I realized I had goofed a tiny bit on the gauge and that very little goof of half a stitch per 2 inches changes the intended width of the back by 2 inches. Dang it.
I had a bad moment when I realized that, I had to face it, accept it, and decided on a course of action. I could give in to my baser impulse and tear it all out, stomp on the hook, and stalk away to 'do better things' til I felt mature enough to take it on again. -OR- I could just keep forging ahead in the hopes that it'll look great on me anyway.
I took the high road. It was mostly because I would have cried to see my work all messed up. So I guess not so high after all. Oh well, the outcome is for the best, right?
It's worked from the hem up and I've finished the waist shaping and I'm on to the arm-hole shaping now. It looks good and I can't wait to get the back done so I can start on the front! It's so pretty.