Whats the status on your inventory of assassin snails? Is there a minimum order for them? A really tiny box with a couple heat packs would work well I think! Are they as hardy as mts? If they are then cold or hot wont bother them, I cant kill those things!
With shipping the Asassins, it's abolutely necessary that they do not reach 56F during shipping.
I have about 160 available. I don't have really small boxes, most of what I have is the standard 7x7x6 boxes.