Skirt supports are an important part of getting the right look for 18th century gowns. The look I'm going for is like this ca. 1790 Self Potrait with Harp by Rose-Adélaïde Ducreux.
The skirt is rounded in the back instead of on the sides as it would be earlier in the 18th century. Kendra at Demode has written an article about 18th century skirt supports that is available at Foundations Revealed. Kendra tested a bunch of different pad designs that she adapted from contemporary depictions and extant garments. I decided to do a variation of one she created from the a satirical print "The Bum Shop". From the number of similar bumpads on blogs this seems to be a popular option.