Homebrew PCBs

I've been watching this with interest.  For me the biggest questions
are   
a) cutting electrode design (shape, material, ...)
b) spark control
c) power supply

cnc stuff is well documented on multiple forums but there seems to be
little info on the above issues.   I sure hope a simpler power supply
design exists than the one on Garden of EDM.

Please post what ever info you have.

Thanks,
Phil