Regarding cables:

Yes, I've always made cables. Been selling PSU breakout boards for a little over three years and they've always shipped with in-house-manufactured cables.

The cables I made for this build are 24" from EVGA 8-pin PCIe (and CPU) split to two PCIe 6+2. 18AWG wiring is necessary for doubling up in a pin (double 16AWG is too much wire for a solid reliable crimp) but that's still good for about 150W per end, meeting PCIe 8-pin spec.

Not sure if they're in use in this build but I also supplied some 6-pin to 4-Molex for riser power, plugging into the EVGA's SATA/RERP ports.