20long before he was moved into here, I'm thinking about getting a 30long just to decrease height but I may as well get a plasitc or something, be nice to make this work though...I covered half of it with a couple towels and stuff
A 20 long can hold an adult for it's entire life.
Theres no reason to move up in size from that. A 40 is too big and will make him feel insecure.. a 30 would be the maximum for a full adult, and he's not even a complete adult yet.