FYI- my first LED DRL attempt was aborted because the first LED wouldn't light up, though the lamp proved good once I removed it from the car and went back to incandescent. Though Martin Winlow was able to run a mixed pair in the post that started this thread, I now think the incandescent that was still burning in the second socket prevented the LED from lighting up (though I had thought the LEDs had less resistance).
So, when I get the time I'll re-install BOTH LEDS and see if they function properly.
Moral of the story? Half-measures might not work....