Before I took over the UO-8 as my commuter/beater, my wife had the straight-ish upright bars that came with most of the Peugeot UO-18 mixtes, along with Schwinn TwinStik stem shifters. Barcons or thumbies, both still relatively rare in the early 1970s, might have worked, but I can see where someone would not want downtube shift with upright bars. When I built her a mountain bike, since she prefers trails away from traffic, I decided to try barcons when I converted the UO-8 to drop bars, since I already had the downtube cable stop in place for the stem shifters. I have been delighted with them.