to use the 6x8 font, 
	             cat clocky-font.py >>/home/pi/.local/lib/python3.5/site-packages/luma/core/legacy/font.py

 
or wherever the luma-core font.py is. This can be found by running python manually:

python3
>>> import luma.core.legacy.font
>>> luma.core.legacy.font
<module 'luma.core.legacy.font' from '/home/pi/.local/lib/python3.5/site-packages/luma/core/legacy/font.py'>