> Does some guide exists to create the CHDs for this emu?
> I am interested in doing this if anyone can point me in the right direction.
> Which sets do they originate from?
the only way to create chd is convert GDI raw images with CHDMAN tool from mame. but since new CHDMAN uses new compression methods, and more important GDI conversion isn't working at all, you must use older version, which is too can convert GDI just by accident as R.B. told before