I was experimenting with the Da Vinci LTW, and when I did sculpting I had a surprising amount of fun. The discoveries of statues and furniture (even a functional sink!). Now, on the numbers, I had born salesman so it may be a bit skewed. The material you sculpt with determines the length of time a sculpture is modified by, and a cost modifier, and each sculpture type itself is sometimes faster or slower. The "best" from my guess would be the modern flame statue that was relatively fast (maybe three hours after getting the skill goal) and when made with stone sold for over 2k base without masterpiece or brilliant, and if you sold at consignment could go all the way to double that value. I believe a masterpiece sculpture I had sold at consignment for around 12k. With the new consignment store and its traits, combined with the way you can customize a sculpture based on material, type, and quality, I think it is going to become difficult to really determine its hourly best wages.
I'd like to hope it all turns out roughly equal between painting, inventing, and sculpting, because I like them all, I'd like to just switch between them as I feel like on the Da Vinci sim to make money.
The increase in speed from the skill is fairly significant, meaning I could churn out up to five or six ice sculptures a day, more if it was something faster like clay or topiary. So, getting 1000-2000, I was making some good change. That isn't even including the occasional brilliant or masterpiece. The only sculpture type I couldn't figure out how to do was how to sculpt a person. I got a wish for it, but never could fill it. I'm wondering how long those take, and what those are worth.
Edit: That 12k masterpiece was also an ice sculpture, not a stone, so it could have been worth more. I made a clay masterpiece lion statue once, and it sold at consignment for about 5k. So the material does matter, and certainly affects speed. A bit of a "hack" that I found was that I was making the sculpture in my basement, with no decoration. After I was getting "free" materials from the skill goal, I would do this: As soon as I started a long sculpture like stone, I would notice IMMEDIATELY I'd get either decorated, nicely decorated, or beautifully decorated buff for the room. Each seemed to correspond to normal, brilliant, or masterpiece works I was doing. So, long before I completed a sculpture I knew if it was a masterpiece or brilliant and I could ditch the normal stone sculpture since they take too long to only get a "normal" one. Granted, you can't do this until you get free materials, otherwise you are throwing 500 $ out the window each time. Plus, it is a bit tedious, and you could get really unlucky and go hours without getting a brilliant or masterpiece, but that masterpiece might really make it worth it.