What a beautiful old skillet. The key with vintage cast iron is to make sure the pan sits flat and hasn’t warped, although this will matter less if you’re cooking over gas. I bought an old Vollrath recently on eBay but wound up returning it because it was subtly warped.
I’m surprised no one has mentioned what exactly seasoning is. It’s not the fat becoming carbonized or building up in crusty layers mixed with charred food. It’s actually the fat polymerizing, that is, literally becoming a form of *plastic* where its molecules bind together in long cross linked chains.
A well formed seasoning is nearly impervious to soap and scrubbing.
The key to a good initial seasoning is to use only a very thin layer of fat. You should wipe it all around, then wipe it out with a dry towel. It should look almost dry. Too thick and you get a superficial seasoning that isn’t fully polymerized. It’ll be soft and weak. Better to build up in thin layers.
I don’t own any non-stick pans. I do eggs in either cast iron or carbon steel.