"Maybe there is something magical these fuses impart."
I suspect you were probably right the first time, that bypassing the stock fuse with pure copper is better than any fuse, with the caveate that you take care to protect the exposed copper wire from local magnetic fields and RFI/EMI and vibration. And that the copper wire is inserted in the correct orientation.
I suspect you were probably right the first time, that bypassing the stock fuse with pure copper is better than any fuse, with the caveate that you take care to protect the exposed copper wire from local magnetic fields and RFI/EMI and vibration. And that the copper wire is inserted in the correct orientation.