okay, here's the basic idea of how I would do the panels:
In my experience, corsets don't really work out without pinning. But the measurements to draw the pattern would be chest under the breasts, stomach, hips at the point where you want the corset to end. The width of the front panel at the top would be the width of the opening. Subtract this width from the measurement, divide the rest by 3 to get the widths of the other panels in that area. The other measurements get simply divided by 4. If you want an actual corset, you'll need to add boning - I'd add it near where the panels come together.
I actually intend to make a shirt like this when I return to the states. So if you want a full fledged out tutorial, I can put one together after the 21st.
Hope you find this helpful, good luck with your project!