Tolivac,
I'm gonna pass on the National(well at this point I am) as I have the same model in the collection already. The SS5000 that I won will be #2 for the collection.
My exposure to Waste King was the same as it was for ISE. Somewhere someone my parents knew had a Wards disposer(or from my exposure to Wards Catalogs) I knew Waste King as Wards first, just as I knew ISE as Kenmore.
To the best of my memory all Waske King models had the cast grind ring, up into the early 80's, and then it was just the low end models to have the stamped ones. Waste Kings were expensive machines too, back in the late 70's the SS 5000 was a $150 machine, although the ISE 77 was more expensive yet.
I think Wards went to the Anaheim made models because Waste King just got too expensive.
Around here Waste King was widely available at hardware stores as well as the home centers, however they went away for a while and then re-appeared in the early 1990's with the plastic mount. The other brands that home centers sold was Emerson(ISE made) and Sinkmaster(Anaheim)..ISE appeared on store shelves here about 1992 at Builders Square.
Waste King was absorbed by Anaheim about the same time, for a while they used Waste King's designs, but it was not long before all Waste Kings were the Anaheim permanant magnet machines.
The one thing that Anaheim kept was Waste Kings three bolt mount, which they still use today on Waste King Custom series models and Whirlaway PRO models.