Ken,

I use both types of chains on different bikes. Personally, I would be less preoccupied about the miniscule weight differences, focus more on the other drive train parts, and just use whatever chain those parts require. The extra width of the chain has no direct benefit; however, the nicest roundest chainrings are high end 1/8" track chainrings, so for that reason alone its worth considering a 1/8" chain. My Sugino Zen chainring is more perfect than any other ring I've ever used...the chain is the exact same tension at all points during the rotation of the cranks. For that reason, its just unbelievably pleasant to ride in comparison to my 3/32" rings which have always had at least minor (sometimes major) tight and loose spots. If perfection is what you want, then you should look into good 1/8" track chainrings.

As far as chains are concerned...I've tried lots of chains, including expensive NJS chains and I always come back to the the KMC Z510HX for 1/8" and the Z610HX for 3/32".

Having read many of your past posts, Ken, I'm certain you will put way more thought into this than anyone else would ever bother, so I'm very curious to see what you come up with in the end.

Good luck!