If I'm doing a bunch of them, I just lay a single layer of briquettes on the lower grate and cook all of them direct, turning every 5 minutes or so. Takes 20-25 minutes and they should be done, check with thermometer though.
I do them indirect sometimes too, doesn't take as much tending.
Edit: I just noticed your using a gas grill, in college we would set our gas grill to 350 degrees with the lid shut and turn them every 5 minutes or so.