I would not worry about the cold, at 6 weeks, unless it gets 20 to 30 degrees BELOW zero. If it is above 20 degrees, and they are out of the wind, they will do fine.
As for how much they eat, I would guess about a tablespoon. What I would do is feed less than you think, but feed twice or three times a day, making pretty sure it was empty. Placing the feed dish on a tray can save a lot of feed, as a lot of feed gets wasted, when they scoop it out of the bowl. Just pour it back in there.
More space is better. Just healthier and they should be out in the sunshine too.
Mrs K