This is by far the best feeder for nucs, its very versatile.

Measurements for 1/2 plywood
bottom 10 1/2 x 20
sides 3 1/2 x 20
ends 3 1/2 x 11 7/16
Top 11 1/2 x 21

affiliate link to purchase rapid feeders https://amzn.to/2Mze6GQ

1:1 sugar water video link: https://www.youtube.com/watch?v=WlOoU8sTxqI