Let's just get this out of the way:
I've made my second muslin and this time I used fleece which is closer in weight to the wool that I've chosen. So, what changes did I make? Here ya go:
I made the lapels and collar slightly smaller. I think I like this better. And I deepened the armscye 3/4". That seems like a lot, but it feels so much better, and will allow those winter clothes that eventually we may need. (The ceiling fan AND another fan, plus the AC, are going for this photo shoot!)
I stuck with the size 10, but graded out to a 12 at the waist on all the seams and then back to the 10. Then, when I stitched the princess seams, about 2-3" above and below the waist, I used a 1/2" seam allowance, then back to the 5/8". I don't think that will be necessary at all on the front and will stick with 5/8" SA all the way.
Now for the back view:
The thing I'm most concerned about on the back is how the shoulders look kind of droopy, and it generally seems a bit too wide. I'm wearing sweater underneath, and it's plenty comfy, so I think I can do a bit of narrowing at about the halfway mark on the armhole on up to the shoulder on the back and the front. No more than 1/2" narrower. I'll unstitch and try again and see what happens.
I'm feeling pretty good about this version, and it will come in handy as a bathrobe, I think. Or not.