So many different ideas, some more drastic then others, but what ever method you choose, My first knee jerk thought was the Concave down and the Convex up, seems to me that would lessen any rocking or need to shim it. Then flip it. But as Herb said, you would lose a lot of material in thickness that way. I never would have thought of his idea of splitting it and reglueing Please be careful and post your results . I for one would like to see how you do it and what the out come is.
I am missing Stick´s reply.
We, woodworkers are everywhere!!!