I'm pretty sure they should all work fine on +/- 12. The only issue I know of is that the CD4021 CMOS chip has a max operating voltage rating of 18VDC. This could be easily addressed by adding 9 volt regulators to this board in the proto area and everything else could run off 12V. I'll have to check and confirm though. 
 I'm getting the PCBs in the mail tomorrow (!) and will be posting pics, vids, etc hopefully reporting on my success.