I took in the sleeves by 1" and the sideseams of the dress by 2" from underarm to waist, and by 1" from waist to hem, that seemed to fix the problem! The muslin still has some weird looking folds, but I assumed that it would be fine when done in wool crepe, and I was right! (phew...)

I finished the dress saturday evening, just in time for partying! It's definitely not a "serious dancing" dress, (even though it's really comfortable!) it does get very warm, which is good when you need to go outside for some fresh air. And I wasn't even wearing tights!

I'll post some more "technical details" when I take proper pictures, for now, here's me trying to be Lucille Bluth:

Ice cream sandwich!! and me attempting a Lucille Bluth facial expression.

(the last two pictures show the color quite well, it's an almoust blue purple)