Vape display holder

This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/g9VxaFDJnSQ


First time trying tinkercad.
I sell 4n1 vapes at a local flea market.
ive been looking for a way to display them other than just leaving one of the cases open.
this is the design i came up with but now im stuck bc i dont know how to make the tubes hollow or the wells hollow for the bins. also im not sure how to gauge the tubes on tinker cad to the barrel sizes.

any suggestions. ?? im new to designing.
and 3d printing as ive only owned my Ender3 going on a month now. i also use Cura. thanks in advance.