Sounds like a good technique, I'll remember it if I ever find myself with more babies than I can monitor together. What happens if they don't feed on the second chance? Are you keeping feeders and non-feeders separate? Or do they all go back in the housing bin after the feeding session?
If you don't separate feeders from non-feeders have you considered doing it so that you can leave the non-feeders in a container with food pieces for longer (like overnight)?