I am an amateur student of historic costume, and I have an extensive costume library (mostly boxed up while my sewing room is renovated--um, Steve?). I have that corset book, too. I also took a corset-making class with a historic costumer and we made an authentic Victorian corset, with cotton coutil and steel stays and all the rest of it. A couple of notes you might be interested in--our instructor was a very full-figured woman (BBW), and she said that wearing a corset was far more comfortable for her than wearing any kind of bra, because it supported her around her torso, rather than putting all the weight on her shoulders. It also gave her a more flattering silhouette.
My corset is fairly comfortable also, as long as it is not tightly laced. (I believe the book says that tight lacing was only done for evening/special occasions and was not an everyday thing, despite what we tend to believe in modern times.) Even when it's tightly laced, it's not painful, just really restrictive. I can't breathe deeply, kind of like when I have bad bronchitis.
As you might already know, there is a subculture of corset-wearers, and if you want more information about what it's like to wear a corset regularly, you might search online for groups to question. Here's one Web site: http://www.romantasy.com I know there are lots more.
There's a man in Paris known as Mr. Pearl who makes super-expensive custom corsets for Dita Von Teese and anyone else who can drop a few thousand $ on one item of clothing. His work is beautiful--I saw it in Vogue. I always thought that custom corset making would be a fun job to have (if I could get paid what he does).