Update:
I tried tempering the 5/0 stock Victory jig hooks with my 1000 degree heat gun, and the eyes still snapped. Same with the Mustad hooks.
So I used the propane torch to get the hook eyes red hot, let them cool on the metal tray I use under my lead pot when I pour, and then opened the eyes with an awl, driven through the eye into a piece of plywood.
Then I loaded the hooks into my jig mold, and poured six 1/2oz heads.
I powder coated the heads at 350 for 45 minutes, added my skirts, and crimped on the chatter blades. No breakage, and the eyes were hard enough to close to make me confident that they wouldn't open up on a fish.
I don't know if it was the hot lead, or the baking at 350 when I powder coated, but something worked.
I didn't try any 4/0 or 3/0 hooks, since I don't need any smaller hooks for my chatterbaits. If I do, I'll report back on what works, or doesn't.