Something I haven't seen remarked on here much, is the similarity between a Rohloff and a single-speed as regards not chainline, but chainring concentricity. I was fiddling with ratios today, and put the 42 on the front, in place of the 46. The 46 came from Universal Cycles mounted to the Sugino crank, and must have been carefully place, for the chain rain smoothly over the rear tensioner and cog. But with the 42, the chain was dancing around a bit and I could feel and hear the vibration. Which is fine for Sunday morning with my sweetie, but not great when just spinning the cranks. I pulled out my dial indicator, and sure enough, the new ring was off-center. Some persuasion and careful iterative retightening of the bolts brought it into near-perfect centeredness, and the tensioner calmed right down. Perfection!
Or, maybe I just need to back off the Surly tensioner! But better to have a smooth chainring than something trying to approximate a Shimano Biopace...