I was able to locate a slightly used wheel today at a good price with SON20 dynamo, so I decided to take it. For me, the dynamo will provide big benefits on both the overnight brevets as well as the early morning commutes. I sometimes forget to charge my batteries for a few days when commuting. This will keep me from having to worry about exhausting my batteries on a dark road.

Thanks for all the good comments. After I get the lights, I'll probably test them on both the dynamo and the 5V DC source and report back here.