Pick which format downloads using content server

I used content server to add all my books to CC. But it keeps wanting to default to epub. I unchecked epub format in settings, but it didn't make a difference. I prefer AZW3, because then I can use the kindle app to read the books. But I always get the books in epub, and convert.

1. Is there a way, either in CC or Calibre, to control what format downloads with content server? I am transferring a lot of books, so I want to do it once. I started fresh, redownloading, and as long as epub is unchecked, I am good.

2. Is there a way to choose which format CC opens? My book opened in epub, but it shows both formats. Just tapping on the AZW3 doesn't do anything.

3. Is there a way to delete one format in CC? I have epub, AZW3, mobi and PDF. I would like to delete epub.

4. Is there a way to block the tag 0read0?

Thanks for all your help.

Debra