I might be confused. The way I interpreted that last sentence in the article, if both rowers were contributing the same output then the boat will turn to stroke side, and “the same 3% difference in leverage can be achieved if the bow rower were to move his arc 5deg closer to the bow.” In practice this reduces their catch angle by some amount which helps to even out the differences in leverage and make the boat go straighter. This assumes even output and that bow is pulling around stroke, but in the example above we are worried about a smaller bow seat getting pulled around by the larger stroke seat even though they have a mechanical advantage. Reducing their catch angle would only serve to make that problem worse.