Where can I get some, and which is the best?
Sounds like you want a lot of it for shooting use, not individual cases for a collection.
Check GunBroker.com or other auction sites.
It is probably more important to get a large quantity of the same lot to ensure consistency than to worry about a specific year or maker (FA or LC), so use what you can find.
We will not get into any specifics on reloading on this forum, so you are on your own for that, but other sites are loaded with such advice.
FA and LC National Match brass is often for sale on the auction sites. But, if I was you, I’d look at buying some new match brass from the likes of Federal or Remchester.
Don’t forget, the newest Cal .30 NM brass you can find is 42 years old.