The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
The river is too kinky to ever become a true "destination" river. But that's part of why I like it, and can even mention it without worry of mobs of anglers.
Aside from the early and late part of the season, being on the water before dusk was a waste of time (if there is such a thing while fishing). Day time revealed many chubs and the occasional very small Brown as you state. I found that I had to be on the water daily to be successful, the river and fish are very finicky about revealing secrets. I have seen the blizzard hatches with nary a rise and I have seen the water come alive with feeding trout. We all know that the chance of success is directly proportional to time spent on the water, but the Namekagon takes this to a higher level. If I missed more than a couple of days in a row it was like starting all over again. We have all heard the experts expound on the Brown’s nocturnal habit and the Namekagon Brown is the quintessential nocturnal.