This is Butterick B5490, Suzy Chin pleat front dress, made up as a muslin. I was semi-careful with the bodice pleats, but the skirt pleats are pretty much randomly just basted in place at the seamline where the skirt attaches to the bodice. I cut a straight 10, but had to use 3/8th inch seam allowances on the waist piece, and it's still a smidge tight there.
The reviews I read of this pattern on Pattern Review all mentioned the bodice pouffiness, and indeed- that's going on here. I think I'll be fiddling with trying to fold out a bit of the extra at the upper chest, but that's going to be a little weird to do with the pleats.
Also, I'm less of a fan of the waistband piece as made up, although it does look nice in the pattern picture. It might be that it's just the light scrap cotton I used for the waistband in this muslin, and that's it's still a little too tight.