Moved this over to the official QMK Firmware repo as a custom Spaceman Spiff Keymap.
Once I figured out that cloning that repo and working with their make build process was straight forward I was much happier with that than the web editor.
Spaceman Spiff layout for GH60
This repo was created for a GH60 Satan (a.k.a. RevCHN or GH60 China), which uses a atmega32u4 microcontroller.
Layout created with http://kbfirmware.com/
The layout files can be found in gh60spacemanspiff.hex and flashed to the keyboard using the QMK toolbox GUI App or via the command line with the flash.sh script.
The flash script requires dfu-programmer to be installed:
brew install dfu-programmer