I am currently using manual focus for my 80mm so i decided to make a Bahtinov Mask.
I use the calculator from the website -
http://astrojargon.net/(X(1)S(vehrpv...Generator.aspx
Based on my Light box I made some time ago, I used some foam to circle the lens and place the mask on top.
The mask is printed on Photo paper then laminated. After which I spent a very long time (about 1 hour) to carefully cut out the slits.
I can't show a picture of the mask yet but I have the results. The camera is currently taking images out back.