New Snake recommendations

Does anyone have an idea of a snake that I should get for a rack system, the tubs are 16-17 in. wide and 33 in. Long. The height doesn’t matter I’m guessing but it is 5.5 in high. The largest gap isn’t even 1 in, also wondering if that gap would have to be covered. For safety, also for the reptile recommendations I would like a good seller so I can look at the ads.