The original shaping used a minimum of dimpling. At the tightest radius point it's ovalled a little, but none of the pronounced dimpling or flattening that is often done. Builder tried and succeeded at keeping the CS tube as round as possible. It's fully round at the BB shell, where the tubes exit at an angle of perhaps 20 to 30 degrees from center plane.
I suppose what I'm worried about is accumulated work-hardening due to repeated bending.