what kind of optics would you put on a 358 nm, ie: 1.5x6 3x9 2x7 ???
I run a VX-III 1.75-6X32 on mine, and it's perfect. But it hasn't escaped me that it lives on 4X. I would be just as happy with a straight 4X.
As for the scope, Leupold. See above.
Re brass, I haven't tried A=Square. Winchester 300Win brass is readily available, outstanding in quality, very tough and cheap. I can't imagine not using it.
I can't say the long necked Norma is any better than the standard, but it has attributes I like. If you are using a magnu length action, I can't think of a single reason not to go this way.
With that magnum action, you can also go with the 35 STA. But for me the Norma in an 8 pound rifle sans muzzle brake is enough. It shoots plenty flat enough and doesn't kill on both ends. It's a good cartridge.