Thanks for all the input. I tried rowing through the gears twice before I drove off yesterday afternoon and it didn't give me any trouble at all. It was still a balmy 21 degrees which is usually cold enough to cause difficult shifting. I'll have to keep an eye on it and see if the improvement lasts.

I've played with the idea of installing a short-throw adapter but not too seriously. Why would that help? I would have thought that the loss of mechanical advantage would make it somewhat worse.