OOT boxes....

I want to order gable boxes... but I'm not sure what size. I want to be able to put water bottles in there... do you think 8 x 4.875 x 5.25 is big enough or should I go for the next size up... 9 x 6 x 6?

I am going to order that 9x6x6 I am afraid the smaller size will not be big enough!