For four snakes it wouldn't be worth building a rack that holds shoebox sized containers. I would build one that holds sweater boxes. But - are you planning on getting more after the new '3'? Because if not, building a rack to house only 4 snakes would probably be more trouble than its worth.
0.1 Ball Python, 0.1 Creamsicle Cornsnakes, 1.0 Amelanistic Cornsnake, 1.0 Ghost Cornsnake, 1.0 Motel Amelanistic Cornsnake, 1.0 Okeetee Cornsnake, 0.1 Striped Amelanistic Cornsnake, 0.1 Silver Phase Miami Cornsnake, 0.1 Sunglow Cornsnake