I don't know that I can shoot any accuracy differences there might be between turned and unturned necks or between necks sized on the inside vs outside. My good guns shoot groups in the 0.1"-0.3" range, and that's plenty good enough for me. I run Lapua brass when I can, and it's pretty consistent in thickness. Not worth worrying about.

I have my dies honed to the dimension I want based on bullet dimensions and brass thickness. Chamber dimensions do not come into play.

I trim when I do only to make it fit into my process. If I trimmed after sizing, I wouldn't be progressively reloading anymore.

I anneal after every firing. It's fast and easy, and I think I get more consistent resizing and neck tension that way.