expanding the article window

[Daniel C. Bastos]

I (setq gnus-use-trees t) because I like to see that; but then sometimes
the article window becomes too small. I'd like to learn two things: 

(1) how to expand the article window with a keyboard shortcut for when
I'm on the console and so unable to open new frames on a new window.

(2) how to keep a new frame just for article reading (and possibly
following-up-to) and another just for the summary and tree view. Because
although I may keep a second frame with the article, the other frame
(the main frame) still opens the article in its own window defeating the
purpose of using a single window for the summary.

Just point me to the manual if there's a section that answers these
questions. Thank you.