> I get the full header when going to the next article no matter
> what I do.

> I want permanent short headers.

Do you not have gnus-article-hide-headers-if-wanted and/or
gnus-article-hide-boring-headers in your gnus-article-display-hook?
If not, see if adding one or the other or both does what you want.  I
have both in there, but I'm pretty sure that's from the defaults.  I
get short headers as I want.  Also check that the gnus-visible-headers
and gnus-ignored-headers variables are set the way you want them to
be.