@dlowan,
It continues to be a mixed bag. Night before last, I kept food out all night, and pulled it as soon as Nerm went out on his rounds. No problem when he came in for the midday nap, but he was ready to eat after the second prowl. He wondered around the food place, sat down and watched me for awhile, then checked for the bowl again. The guilt got to me, but then I had to keep him in from 7:00 p.m. till morning, and it doesn't get dark these days till about 8:30.
Same thing today, except he went out for the last time at 6:30. He hasn't been fed for awhile, so maybe he'll be back in a timely manner, and in for the night.
Overall, it's going better than I expected. He's actually been more friendly than usual. Could be he's decided I'm not someone to mess with. Right now, the bowl is on the floor, waiting for him. This relieves the pressure from Spooky, who is not taking the project as well as Nerm. Spook goes outside too, but seems to lack the investigative instinct. He's always in by bedtime, anyway.