Starting different window managers

I start up my window manager (Fluxbox) by command line 'startx'. However, sometimes I want to experiment with other managers and it becomes a chore editing the .xinitrc every now and then. Instead, I use 'xinit':

xinit /home/username/bin/fluxbox
xinit /home/username/bin/beryl
Content of ~/bin/fluxbox:
for errfile in "$HOME/.xsession-errors" "${TMPDIR-/tmp}/xses-$USER" "/tmp/xses-$USER"
do
if ( cp /dev/null "$errfile" 2> /dev/null )
then
chmod 600 "$errfile"
exec > "$errfile" 2>&1
break
fi
done

exec startfluxbox
Content of ~/bin/beryl:

if test -z "$DBUS_SESSION_BUS_ADDRESS" ; then
eval `dbus-launch --sh-syntax --exit-with-session`
fi

emerald &
beryl-manager &

# Start other applications here
#
# Example: set wallpaper + open a terminal
#
#fbsetbg -f /home/username/Personal/Bild/Hintergrund/nix.jpg &
#exec rox -p Default -b Default -S &
exec /usr/local/sbin/rox-session
exec beryl