I created and used this template successfully to build an 8BitM8 kit I purchased from midierror on Tindie. It includes the extra 0.2mm on each hole to allow for powder coating, includes holes for both an arcade button and a footswitch, and because it allows room for an arcade button, it requires the use of open-frame (Lumberg-style) jacks. If you don't need the arcade button, you could move everything down a bit to make room for the jacks of your choice.
Image of final product:
Image of final product:
