The original dress looked more or less like this.
The sleeves are this sort of medium gigot shape. They're held up on the inside with little sort of fans of pleated fabric stuck into the armsceye.
The center front had this large decorative buckle, which was really much too heavy for the bit of fabric holding it up. The actual design of the buckle seems passable to me, although the one missing rhinestone is a bit sad. It's worth noting that this dress saw maybe 5 or so years of occasional wear before I got at it.
The center back buttoned up with large buttons. Like very large. Very plastic, with enormous machine button holes, and this sort of awkward placket situation. I'm not really sure how this closure came about, especially since there are so many way easier period closures.
The neck facing was just a little narrow bit of cloth, cut on the straight if I'm not mistaken, which liked to stick up at all angles.
And under the arms were these weird stains... In the picture it looks white, but it was actually sort of glittery. I don't know if that was well-ripened deodorant stains, failed dry cleaning, or some kind of like febreze. They didn't show when the dress was worn but they were a bit unsettling.
For the design of the dress I'm taking my inspiration mostly from this dress from a Norwegian museum. There are great pictures, from front AND back! It's the exact right year, and it's relatively simple so the style lines are easy to read. The look I'm going for is basically, simple silk day dress for a conservative New England lady who is also trying to be a bit up on the fashion. I'm going to do roleaux trim on the hem instead of ruffles, and probably a simple puff on the sleeve, and I'm putting in a waistband which will be magically adjustable at the back