So I downloaded slackware on dozens of disks.
This is no joke. When I downloaded Slackware in '95 or '96, it was over 100 3.5" floppies of 1.44 MB each. And there were still more available, those were just the ones I thought I’d need. And before you could even begin installing, each of those had to be downloaded, written and verified because floppies were not terribly reliable.
Your typical bike dynamo puts out 6V AC. I bet yours does as well, so that diode sounds like a good idea.