Well, judging by the video I just saw, I'd say Oscar is doing fine on raw! Congratulations on the switch.
For my cats, sometimes I will leave the food out for up to an hour just to let them take their time, wolf some down, go away, lick their chops, come back, nibble a bit here and there and then I'll put it up if they haven't finished everything.
I have noticed that they seem to like to eat this way, better instead of being forced to eat all at once. That may come from when I fed them kibble and had the snack bar out all day long whereas now, they are fed at specific times.
Still, I like to see them relax about it and not feel they have to gulp everything in site...just eat, relax, come back, eat a bit more, relax, come back, eat a bit more....usually by the time that hour is up, they are all quite satisfied and done with it for the night.
I wouldn't leave it out all night though, just a little while.