I've been working on the Moy gown in fits and spurts. I'm actually farther along than is shown at right - many of the seams are finished and flat-felled now, although others are still just basted. I've decided to use machine sewing for assembly, but hand sewing for flat-felling, since that will show through a bit on the front.
The picture is trying to show one of the key fitting adjustments that I needed to make on this dress. The gown has a really bizarre construction, centered around these huge four-sided gussets that go over the shoulder blade. It's like if you took the sleeve and square gusset from a tunic, and rotated it and pulled it back so the lower point of the gusset almost reaches your spine. Anyway, you start with an essentially rectangular sleeve - flat across the top, and it doesn't start to taper until about the elbow. However, the gusset, for the original example and I think for most people, will be longer across the top than it is along the side. Rather than matching the both corners of the top of the sleeve to the corners of the gusset, what you want to do is this. First, match the top corner of the sleeve to the top back corner of the gusset (upper left of gusset in photo). Pin/baste/sew this out to the gusset corner where the sides of the sleeves will meet. Now, match up the sleeve edges starting at the wrist, and work backwards up toward the gusset, trying to match evenly without stretching the top or bottom piece. Just before you reach the corner of the gusset, I recommend tacking the sides of the sleeve together for an inch or two (the rest is left open for buttons later). Now that everything is matched up at the corner, sew the remaining portion of the sleeve to the side of the gusset. You will have a bunch of extra fabric from the sleeve, but don't try to ease it to fit the gusset, just let it hang past the end and it will be trimmed off later (lower right of gusset in photo). As you attach the front of the sleeve to the body of the dress, you can gradually taper down the excess until it is down to your normal seam allowance (additional pictures).
Once I finish these last few seams, I should be ready to start working on the closures. I'd like to find some silk tabby tape to use as a facing and reinforce the buttonholes, like is shown in the MoL Textiles and Clothing book, but I haven't found anything that seems appropriate yet. I'm pretty sure that satin ribbon is not what I want, but I'm not finding much else right now.