Please help me choose a good single-keystroke escape key

[Jason Spiro]

Hi all.  I'm running GNU Screen on Cygwin on one laptop, and on Debian Linux on
another.  (I may switch to tmux one day, as it works much like screen but is
newer.  But I don't think Cygwin ships tmux binaries.)

I want to use a single-keystroke escape key in Screen.  Because I almost never
have more than ten windows open, this will make it easier for me to view each
open window in sequence, from 0 to 9, until I find the one I'm looking for.

I've tried the backquote (`) key but I don't like it.  The key's position is
different on each of my laptops.  This is confusing.

Usually all my screens hold are Bash and Vim.  Sometimes Emacs.

What key do you suggest, and how do I select it using "screen -e"?  I was
thinking maybe F2 would be good.

Thanks in advance,
--Jason