For a small baby like that, I will go for the 6-12 qt tub. Smaller spaces = more security to a baby ball (Or balls in general). They're only $2-5 at Walmart.
Also, darkening the enclosure w/ a sheet or something will calm it down as well.
Try feeding live first to try jump starting a feeding response. But I would wait a little bit before trying so he gets some time to adjust to his new surroundings.