It really doesn't take them extra time to "adjust" to a tub setup, because it's just inherently a proper setup for young ball pythons. If you get him set up, plop him in, wait a few days and see how he does with eating. You have to wait a few days anyway between offering even with your current setup, so it makes no difference.
Now, if he still doesn't take food, you'll know the problem is most likely that he's stuck on live prey, and not a husbandry reason.
Also, how are you preparing and offering his food?