I formed a bunch for a friend some time back. I never have had a 30, but I have had a 357 Herrett and sizing is a "science" Not terribly difficult, you just need to get the knack of it.
I never trimmed first? I don't know how you could as the case "grows" are you size them... I trimmed them after running thru the die with a dremel tool, then finished the AOL on my Lyman power trimmer.
I never fiddled with annealing for this caliber, but used new or once fired brass. New yielded the least "casualties".
Search Bob Milek or Steve Herrett on line and you should have many hours of good reading on the subject.
CW