How does this look?

I set initial to max RPM, and max vacuum, then back it off to where it doesn't kick back.
That's why it seems to 'want' so much advance. In neutral it will be happy with a a lean burn and additional time to make the most with that lean burn.
I find my overall by driving up an incline in first gear, with the RPMs up, If it pings, I back it off.
First gear is generally a fairly light load. Obviously an incline helps increase that load but it is not equivalent of a heat soaked engine going up a mountain in 3rd gear - which is the scenario a street car needs to handle.
I welded the plates in the distributor to limit the distance between the two, and removed the large spring.
The long looped spring is the not very secret sauce for mid to high rpm performance.
I have not recorded the actual curve I have yet.

There's been some 5.9 magnum engine timing info posted if you search.