Plastic sheets can be cut with scissors or exacto knife. Wife has paper cutter with a sliding blade for easy cuts. Use superglue or plastic cement to make cover using 90 degree joints. No PC or 3 d printer needed.
To clarify it was the PSU to GPU PCI cables that were bad, the rest of the Cablemods were fine. I tried every HW swap and SW updates/uninstalls with no remedy. I used the cables that came with the PSU and has been trouble free for over a year.