Wow--lookit all the corsetry!
I make & wear them. Yes, you read that right--make & wear.
If I had my druthers, I'd rather wear a corset than a bra. It gives your back nice support, just like those elastic back-support things do. It shapes your waist, adjusts your boobs, and in general is a Good Thing.
Some types available in the 19th C:
Athletic Corsets, for riding etc, were made of elasticized cotton and lightly boned. Light boning means at the side seams and on either side of the back panels, where it is laced; and by the busk, the snap device for the front. These were in use from 1830-right through to the 20s.
Maternity corsets were designed to support & shape you without crushing you or the baby. It adjusted to fit, with additional panels & pieces. When you were too big you simply 'retired' from the public eye. After you had your baby, you wore a special nursing corset.
Tight lacing seems to be more a male concern than a female one. Most corsets laced down to a 22" waist at the minimum. Most were much larger. There's a lot if surviving Victorian clothing. Most of it falls well within the range of a modern small-medium. Some are quite large, even by our standards. Surviving corsets--and again, there's a lot of them-- don't typically go smaller than 22". Considering that the corset is not supposed to lace completely closed, this should give you an idea of minimal sizes. You are supposed to have a 2-3" gap in the back. If you can lace it closed, you really need a smaller one.
When you first put it on, you lace it as tight as possible. It will feel tight & you may not be ready for the effect. After several minutes your body will adjust, and it can be laced properly.
What do I mean by body adjusting? People are pretty soft & flexible. Guts can be moved around with little effect on their performance. Xrays of women doing extreme 'corset training' show just how adjustable our innards are. FWIW corset training has as much to do with the real corsets worn by real women as it does with rocket fuel--ie, none at all.
One thing to consider is that kids were put into corsets around the age of 3, so when they grew up they were well-adapted to them. Yes, boys wore them too.
While some parts of corsets can be 'mass produced', the best fit requires some tailoring. The ideal is to have someone who knows what they are doing make you a corset. For most women, then as now, that was too pricey. Instead they bought ready-mades & tailored them as needed.
The one drawback comes when removing it. For a few minutes you hurt, as your bones & muscles get back to work.