Funny you should ask about shaft straightness. I have a theory, for the moment anyway, that a perfectly straight shaft is not the answer to complete smoothness. I think that having a smooth Corona involves cancelling different imbalances. For example, I have had a perfect shaft and yet I could rotate it 180 degrees, insert the Jesus bolt and cause more vibration. Therefore an imbalance existed somewhere other than the shaft but was somehow related. And, my smoothest operation has been with a noticeably wobbly shaft. So... a bent shaft may be able to actually cancel an imbalace somewhere else (perhaps in the design!!!) This may not make sense and I am still trying to master dignosing the vibes. Perhaps my next Corona will be the educational tool that helps me pin down the causes of all of this.
As for the drive wire, I don't know. I have never seen a gas LMH and am not sure if they are identical.
Kip