Thanks for the replies.
I would assume CSMC's posiiton will be something along the lines of "any alteration will void the factory warranty." And, since they couldn't control the grip thinning, they would not be willing to say how much it could safely be thinned. Although maybe the best solution is to send the gun to CSMC to have them do the work, which would probably void the warranty, nonethelss.
Franc Otte - Thanks for the info on your gun's grip shape. I imagine such a diamond cross-shape would be one of the simpler conversions, since that shape would easily preserve the spacing between the upper and lower tangs.
ChiefAmungum - Thanks for your comments. I can see how such a shape would fit the hand while preseving tang spacing.
I'll post an update when/as this project proceeds.
--shinbone