You're missing one important step..... creating a ttf font.
Code:
grub2-mkfont --output=/boot/grub2/DejaVuSansMono.pf2 --size=24 /usr/share/fonts/dejavu/DejaVuSansMono.ttf
And add to your /etc/default/grub file:
Code:
GRUB_FONT=/boot/grub2/DejaVuSansMono.pf2
Then re-run the "grub2-mkconfig -o /boot/grub2/grub.cfg" command.
With only a 640x480 graphics mode, the --size=24 may be a bit too large. You'll need to experiment with that.