Wanted a white one for myself selling the remaining 4. Each PCB is flashed to VIAL and tested with my FC660C. The firmware is also VIA compatible or you can re-flash with any Hasu FC660C firmware.
Note: Requires stock case USB hole to be modded to fit. I used a hobby file. I do not know if it fits in the heavy-6. I hope it does but I am not sure.
Fc980c can use the hasu fc980c controller for programmability QMK, VIA, VIAL, TMK. Not sure if there is a model that works from yang for the topre version.
If its usb C you are looking for I made the guide below for some different options (a have a bunch of the ones that work only with USB A to C cables)