I thank you all for your replies. The brake bump I spoke of is attributable, I believe, to the offset between leading and trailing halves of the weld.
The offset from one side to the other creates a momentarily wider rim between the leading part of one side's brake pad at the trailing part of the other side's pad. Even when the ridge has been smoothed down to a mere ripple the widening effect remains.
I've been working on it and am quite certain it will be just fine eventually. All it needs is sufficient patience, beer, elbow grease, more patience, some test riding (long after the beer is finished), more beer, and perhaps more patience.
I'd ridden this wheel 76 miles a few weeks earlier and while it wasn't smooth braking it wasn't terribly thumpy either. The run down Cadillac is what made me decide to address the problem. I have no desire to cheat death again, even if it really wasn't much of a cheat the first time.