Thanks for the well written comments, Dave.
I got the idea of lightening the flywheel on the Savage after cutting umpteen flywheels for Ducatis. I'd knock anywhere from a couple pounds to a lot of pounds (depending on which model the flywheel came from) off of the Duc flywheels. No complaints ever.
We did install an aluminum race flywheel on my bud's 900SS, and swapped back to the steel one. The aluminum one weighed only 8 ounces, as opposed to maybe 4 pounds for a light steel one. The bike had trouble idling, and was prone to stall on a hard stop. Not a prob on the track, but no fun on the street.
I've also installed light flywheels on a lot of Airhead BMWs. BMW put in progressively lighter flywheels for many years, until they went to essentially a stamped steel clutch carrier in '81. Honestly, the light BMW flywheels are prob too light. The bikes now vibrate a bit, which is one thing a heavy flywheel can dampen.
I don't do light Ducati flywheels any more, simply because Ducati now use light flywheels in most of their bikes. Duc decided that there was no need for the boat anchors any more.
Suzuki realized that a lot of the folks being the bikes would be beginners and prob not meticulous about maintenance. The boat anchor flywheel makes for a bike more likely to idle well even if out of tune.
Like it says in my tag line "In theory, theory and realty are the same thing, in reality, they aren't."
Theoretically, the bikes might need the heavy flywheel, in reality, they don't.
My problem now is that I no longer have access to a CNC mill, so the machining would have to be done on my manual machines, which would take way too much time.