The best solutions are often the easiest ones. That applies to many situations in life and in basenji life. After finally learning to walk one basenji in the big city and a neighborhood with LOTS of dogs for her to react two, when my life changed to suddenly have two basenjis to walk it proved to be a whole new learning process.
After initially trying to walk Shaka and Audrey on two leashes, I was finding that they were soon wrapping around me like a Maypole and decided to try the Take Two Leash Extension. It worked well for having them walk ahead of me parallel, but soon it presented a problem. Whenever we passed another dog, they got into a snarling scuffle, sometimes getting into a wrestling matching in the cross walk at four way stops where impatient drivers were ready to run us over as I worked to bring back calm. So I tried a Take Two with a wider extension which made a slight improvement, but we seemed to have a scuffle on just about every walk.
Finally, I have reverted back to the two leash approach, attaching both leashes to my belt. We have some Maypole wrap arounds, but when there is another dog passing, it's much easier to separate them IN ADVANCE, and the scuffles have diminished to about once every other week.
(P.S. The photo at the top is from two months ago when we had just begun Audrey on coat supplements and regular brushing. She has made remarkable progress and is fast to having a perfect, shiny coat.)