I've made a couple of small tweaks to the firmware.

• The buttons can be accidentally pressed and the time changed. Now you have to depress both buttons together to enter set mode and the display will blank 0.5 seconds. After 8 seconds of button inactivity after setting, it will exit set mode.
• The DDS adjustment can be specified in the Makefile, instead of editing tod.c

I doubt if anybody else has this clock but you may find the techniques useful.