I’ve been meaning to take pictures of the early 19th century shortgown I made last year, to show how it looks on me when I’m not six months pregnant, and now I finally have. Actually, it turned into a comparison between early 19th century clothes when worn over different underpinnings. Now this is far from a conclusive comparison: there where many different types of stays, and for all I know less affluent women in some places might actually have used the overlapping bodice lining as only support (these linings are found in simple country women’s dresses and spencers in Sweden as well, but no other supportive garments suitable for that class have survived as far as I know) – it works well enough, though not giving a very elegant silhouette. Each kind of supportive garment will give different results. However limited this comparison may be, it will still give a hint as to how very important the right underpinnings are for the impression you wish to give, and what year you wish to represent.
I used my corded, lightly boned stays with a wooden busk in front. The figure you get with these stays – even someone like me, a somewhat overweight mother of two – is one with a very high waist, bust pushed to the sides, and narrow ribcage. This was fashionable in the early 19th century, especially in the 1810’s. The stays helps with posture, and prevents your outfit looking too much like maternity wear
With the bodice lining you get a decent lift and support, but of the mono bosom kind. It will pull the dress forward a bit if the bust is heavy. It will not help with posture, and won’t hide any fluff you might have. This general look is seen in the very early 1800’s (though I should think most women of fashion would wear some more substantial support), and might have remained among the lower classes for a bit longer, especially in places where stays were not common among ordinary women.
I myself would not wear the clothes of a middle- or upper class woman without some kind of proper stays under them. For some (Swedish) working class impressions though, using the bodice lining for support just might be adequate.