An observation about optimum downwind VMG

In the example where the optimum downwind VMG is 135 deg TWA, the VMG decreases only slightly for greater TWAs but it decreases rapidly for smaller TWAs. Thus it may be prudent to slightly increase the TWA. You won't lose much VMG, but you won't risk a dramatic drop in VMG if you fail to keep the target TWA locked in. Plus, you'll stay closer to your desired downwind waypoint in case the wind shifts. I'm not an experienced racer, but the above strategy seems apparent from the polar diagram.